Wheel Type Research Articles

Optimal design and experimental research on the spiral groove wheel fertilizer apparatus

As the "core" of fertilizer machinery, the fertilizer apparatus has a significant impact on the effect of fertilization operation. At present, the straight-grooves type external groove wheel fertilizer apparatus is widely used, which has the problem that the fertilizer flow fluctuates periodically and is not conducive to precision fertilization. Therefore a kind of the spiral groove wheel fertilizer apparatus is proposed in the paper, and the designed fertilizer apparatus is experimented and optimized by using Design-Expert Software 10 and a self-made fertilizer experiment bench. Taking the fertilization amount and the variation coefficient of fertilization amount as the experiment index, the interaction effects of the groove radius, spiral rising angle, groove wheel rotation speed, and fertilizer tongue inclination of the spiral groove wheel type fertilizer wheel on the fertilization performance are analyzed. The quadratic regression models of multiple factors of the fertilization amount and the variation coefficient of fertilization amount are established. Through optimization and experiment validation, the optimal combination of parameters is determined as follows: the groove radius is 13.5 mm, the spiral rising angle is 62°, the groove wheel rotation speed is 29.4 r/min, the fertilizer tongue inclination is 5°, the fertilization amount is 17.810 g and the variation coefficient of fertilization amount is 5.60%.

Geometry and Kinematics of the Mecanum Wheel on a Plane and a Sphere

This article is devoted to a study of the geometry and kinematics of the Mecanum wheels, also known as Ilon wheels or the Swedish wheels. The Mecanum wheels are one of the types of omnidirectional wheels. This property is provided by peripheral rollers whose axes are deviated from the wheel one by 45 degrees. A unified approach to studying the geometry and kinematics of the Mecanum wheels on a plane and on the internal or external surface of a sphere is proposed. Kinematic relations for velocities at the contact point of the wheel and the supporting surface, and angular velocities of the roller relative to the supporting surface are derived. They are necessary to describe the dynamics of the Mecanum systems taking into account forces and moments of contact friction in the presence of slipping. From the continuous contact condition, relations determining the geometry of the wheel rollers on a plane and on the internal or external surface of a sphere are obtained. The geometric relations for the Mecanum wheel rollers could help to adjust the existing shape of the Mecanum wheel rollers of spherical robots and ballbots to improve the conditions of contact between the rollers and the spherical surface. An analytical study of the roller geometry was carried out, and equations of their generatrices were derived. Under the no-slipping condition, expressions for rotational velocities of the wheel and the contacting roller are obtained. They are necessary for analyzing the motion of systems within the framework of nonholonomic models, solving problems of controlling Mecanum systems and improving its accuracy. Using the example of a spherical robot with an internal three-wheeled Mecanum platform, the influence of the rollers on the robot movement was studied at the kinematic level. It has been established that the accuracy of the robot movement is influenced not only by the geometric parameters of the wheels and the number of rollers, but also by the relationship between the components of the platform center velocity and its angular velocity. Results of the numerical simulation of the motion of the spherical robot show a decrease in control accuracy in

Overview of milling implements for grinding trees and shrubs

The article describes the main consumers of milling tools (mulchers and rotovators) in the context of the sectors of the national economy, considers the classification features and features of the design and layout of these tools on energy carriers. The range of the main manufacturers of milling tools in the Russian Federation, the Republic of Belarus, countries of near and far abroad is described. It is noted that, despite the effectiveness of the use of tracked vehicles in a number of operating conditions, about 95% of this equipment has a wheeled propulsion type. Special attention is paid to the delimitation of the scope of mulchers and rotovators, as well as the possibility of using disk attachments for shredding trees and shrubs.

Design and parameter optimization of air-suction wheel type of seed-metering device with elastic pad for maize

Design and parameter optimization of air-suction wheel type of seed-metering device with elastic pad for maize

Influence of an equal width polygon groove-tooth wheel on feeding performance of the seed feeding device for wheat

This work aimed to investigate the influence of the equal width polygon groove-tooth wheel on both filling and feeding performance to enhance the performance of the seed feeding device of the air-assisted centralized metering device for wheat. This paper conducted an analysis of the equal width polygon groove-tooth wheel formation principles. The EDEM simulation compared and analyzed the influence of the structural types, including equal width triangular, equal width pentagon, equal width heptagon, equal width nonagon, and circular groove-tooth wheel, on seed population disturbance ability, filling, and feeding performance. The simulation results showed that when the rotating speed of the feeding shaft was 20r/min, the average kinetic energy of the seed population decreased gradually, and the ability to disturb the average seed population decreased in turn, but the interval between the adjacent average kinetic energy peaks decreased, and the frequency of disturbed seed population increased with the increase of the number of sides of the equal width polygon groove-tooth wheel. The average kinetic energy of the seed population was significantly higher under the disturbance of the equal width triangular, pentagon, heptagon, and nonagon groove-tooth wheels, increasing by 371.32 %, 209.23 %, 91.02 %, and 53.37 %, respectively, compared to that of the circular groove-tooth wheel. Within the feeding shaft rotating speed range of 10 ∼ 60r/min, the average kinetic energy of the seed population gradually increased in the equal width polygon groove-tooth wheel type feeding device gradually with the increase of the feeding shaft rotating speed. Using the quality rate of seed filling (2 ± 1 seeds/hole) and the missing rate of seed filling (0 seed/hole) as benchmarks, the equal width heptagon groove-tooth wheel exhibited the quality rate of seed filling of 93.98 % and the missing rate of seed filling of 2.78 %. The seed feeding quantity and seed feeding time had high linearity, and the seed filling and seed feeding performance were better. In the range of 10 ∼ 60r/min for the rotating speed of the equal width polygon groove-tooth wheel, there was a positive correlation observed between the average kinetic energy of the seed population and the increment of the feeding shaft rotating speed. The variation in feeding shaft rotating speed exhibited minimal influence on the feeding performance. The bench test verified the performance of the seed feeding device equipped with the equal width heptagon groove-tooth wheel in terms of both seed feeding and seeding efficiency. The results demonstrated that within the feeding shaft rotating speed range of 10 ∼ 60r/min, the coefficient of variation（CV） for seed feeding rate stability did not exceed 2.14 %. Additionally, the damage rate during the feeding process remained below 0.2 %. These outcomes aligned with the requirements of stable wheat seed feeding.

Software Control of the Movement of a Differential Drive Robot for Different Friction Models

Introduction. Designing motion control systems for mobile robots requires the construction of mathematical models. Researchers have repeatedly addressed this topic. In particular, works have been published on the calculations of multiphysical processes, modeling the movement of various types of wheels under certain conditions. In addition, the dynamics of deformable contacting bodies during sliding, rolling and rotation, issues of autonomy and controllability of mobile robots were considered. Note, however, that the dynamics and positioning accuracy of wheeled robots is largely determined by friction. The literature does not present studies on the dynamics of a robot with a differential drive taking into account the interrelationships of sliding, spinning and rolling friction effects based on the theory of multicomponent friction. Research in this area can reveal new dynamic effects. Based on the data obtained in this way, it is possible to improve the accuracy of positioning in building mathematical control models. The presented work aims at investigating the movement of an automatic device with a differential drive taking into account three contact models: nonholonomic, Coulomb friction, and multicomponent models.Materials and Methods. The scheme of a two-wheeled robot with differential drive and continuous movement on the support surface was adopted as the basic one. The movement of the device was provided through software control. The dynamics was described in the form of Appel equations. Mathematical models were used for calculations, taking into account friction in different ways. Coordination of the actions of the mechanism was formed at a dynamic level. The control actions were the moments of the wheel motors. When visualizing the models under study, the built-in numerical methods of the Wolfram Mathematica system were used with a minimum accuracy of 10-6.Results. When building a mathematical model, the equations for the angular velocities of the wheels were determined. The authors took into account the presence of a contact site and derived the equations of dynamics of a differential drive robot. The elements of the system were force and moment projections, indicators of platform spin, masses, angular accelerations, and inertia of the wheels. It was shown how control actions were formed within the framework of nonholonomic mechanics. The model of engines that created a moment of control on the driving wheels was described. The solution was derived as the relationship between the inductance of the conductors of electric motors and the operation of the power supply. Three models describing the dynamics of a differential drive robot were examined in detail. The first model was nonholonomic. The second and third included a system of equations for the dynamics of a differential drive robot for a general case with a contact platform. At the same time, in the second model, the switching time in the engine was ignored and the Coulomb friction was involved. In the third model, a parameter to determine the speed of transients in the engine was introduced, and Pade decomposition was involved. This was a model with multicomponent friction. The calculation results were shown in the form of graphs. On them, the studied models were visualized in the form of curves of different colors. Comparison of the graphs showed in which cases, after the completion of transients, the control provided the required accuracy. These were models 1 and 2. In model 3, the software control generated an error in the angular velocity of rotation of the platform. This error could not be predicted within the framework of the 1st and 2nd models. In all the systems considered, the sliding speed of the wheels in the transverse direction dropped to zero. The condition of continuous motion of the support wheel was obtained and validated.Discussion and Conclusion. Software control is acceptable in models that do not take into account wheel friction during simultaneous sliding, spinning and rolling (general case of spatial motion). However, it is important to consider the relationship between these processes and multicomponent friction. This is required for the robot to perform program movements more accurately. It was established that software control in a model that takes into account the friction of spinning and rolling caused deviations from the program values of the angular velocity of the platform. The results obtained can be used in the building of a control system with predictive models.

Roman Lamps Discovered at Romula (I)

"This article presents a batch of lamps discovered, in 2022, in the central area of the Roman city of Romula. Import lamps of the type Loeschcke VIII/Ivanyi VII, Loeschcke X with the marks FORTIS, IANVARI and OCTAVI, respectively Loeschcke VIII/Bailey Type K. They circulated from the second quarter of the 2nd century AD to the middle of the third century, with greater frequency from the second half of the 2nd century to the first third of the 3rd century AD. Lamps of local production are of the type Loeschcke VIII, similar to Ivanyi VII, Loeschke X with the mark FAOR, IANVARI, respectively modelled to Alicu XXI type wheel. They have been discovered in archaeological contexts dated from the second half of the 2nd century to the penultimate decade of the 2nd century AD, one lamp of Loeschcke X type with FAOR mark, another with the same mark being dated to the last decade of the 2nd century AD, and the first third of the 3rd century AD. Loeschcke VIII lamps were dated, similar to Ivanyi VII/Bayley O-Q/Ponsich III B/Deneauve VIIA, Loeschcke X with IANVARI stamp, respectively Alicu XXI type lamps. In conclusion, there are more numerous occurences of imported lamps between the second quarter of the 2nd century AD, and the first third of the 3rd century AD., with a higher frequency in the second half of the 2nd century AD. Lamps of local production begin to circulate in the second half of the 2nd century AD, until the middle of the 2nd century AD, with greater frequency from the last decade of the 2nd century AD, to the middle of the 3rd century AD."

Pick and Place an Object with Robot Gripper Using Arduino

Abstract: This paper presents an automatic system that picks an object from one location and places it in another location. A rover features with special type of wheels called Mecanum wheels. A pre-defined path is designed, and the rover is programmed to move the rover in the desired path. The Arduino IDE software tool is used to write the program and the program is being dumped into the microcontroller. A gripper with two arms is used to pick and place objects that are functionally similar to a hand.

Stability Analysis and Navigational Techniques of Wheeled Mobile Robot: A Review

Wheeled mobile robots (WMRs) have been a focus of research for several decades, particularly concerning navigation strategies in static and dynamic environments. This review article carefully examines the extensive academic efforts spanning several decades addressing navigational complexities in the context of WMR route analysis. Several approaches have been explored by various researchers, with a notable emphasis on the inclusion of stability and intelligent capabilities in WMR controllers attracting the attention of the academic community. This study traces historical and contemporary WMR research, including the establishment of kinetic stability and the construction of intelligent WMR controllers. WMRs have gained prominence in various applications, with precise navigation and efficient control forming the basic prerequisites for their effective performance. The review presents a comprehensive overview of stability analysis and navigation techniques tailored for WMRs. Initially, the exposition covers the basic principles of WMR dynamics and kinematics, explaining the different wheel types and their associated constraints. Subsequently, various stability analysis approaches, such as Lyapunov stability analysis and passivation-based control, are discussed in depth in the context of WMRs. Starting an exploration of navigation techniques, the review highlights important aspects including path planning and obstacle avoidance, localization and mapping, and trajectory tracking. These techniques are carefully examined in both indoor and outdoor settings, revealing their benefits and limitations. Finally, the review ends with a comprehensive discussion of the current challenges and possible routes in the field of WMR. The discourse includes the fusion of advanced sensors and state-of-the-art control algorithms, the cultivation of more robust and reliable navigation strategies, and the continued exploration of novel WMR applications. This article also looks at the progress of mobile robotics during the previous three decades. Motion planning and path analysis techniques that work with single and multiple mobile robots have been discussed extensively. One common theme in this research is the use of soft computing methods to give mobile robot controllers cognitive behaviors, such as artificial neural networks (ANNs), fuzzy logic control (FLC), and genetic algorithms (GAs). Nevertheless, there is still a dearth of applications for mobile robot navigation that leverage nature-inspired algorithms, such as firefly and ant colony algorithms. Remarkably, most studies have focused on kinematics analysis, with a small number also addressing dynamics analysis.

Expression Atlas update: insights from sequencing data at both bulk and single cell level.

Expression Atlas (www.ebi.ac.uk/gxa) and its newest counterpart the Single Cell Expression Atlas (www.ebi.ac.uk/gxa/sc) are EMBL-EBI's knowledgebases for gene and protein expression and localisation in bulk and at single cell level. These resources aim to allow users to investigate their expression in normal tissue (baseline) or in response to perturbations such as disease or changes to genotype (differential) across multiple species. Users are invited to search for genes or metadata terms across species or biological conditions in a standardised consistent interface. Alongside these data, new features in Single Cell Expression Atlas allow users to query metadata through our new cell type wheel search. At the experiment level data can be explored through two types of dimensionality reduction plots, t-distributed Stochastic Neighbor Embedding (tSNE) and Uniform Manifold Approximation and Projection (UMAP), overlaid with either clustering or metadata information to assist users' understanding. Data are also visualised as marker gene heatmaps identifying genes that help confer cluster identity. For some data, additional visualisations are available as interactive cell level anatomograms and cell type gene expression heatmaps.

Yawing stability and manipulative approach design for maglev car based on active disturbance rejection control

AbstractIn the present work, to realize the stable static suspension of a new type of electrodynamic wheel (EDW) magnetic levitation (maglev) car without track constraints on the conductor plate. Design and analysis of the active disturbance rejection control and explicit complementary filter (ADRC‐ECF) have been presented to solve the maglev car's yaw angle disturbance rejection under low lateral damping characteristics. Simple and efficient ECF helps to filter the high and low frequency noise generated by EDWs when rotating at high speed, to obtain accurate data in real‐time. Design and build the hardware control system for maglev car, and conduct experimental comparisons with PID controller to verify the effectiveness of suppressing yaw angle disturbances. Based on simulation and experimental results, it is shown that both PID and ADRC‐ECF can improve the stable yaw angle convergence of maglev car under external disturbances. However, ADRC performs better in resisting disturbances than PID and can achieve more accurate fixed angle steering. This paper is the first attempt to control maglev car on a trackless conductor plate for precise steering and anti‐disturbance, which is anticipated to have some reference significance in this field.

Power Consumption Modeling of Wheeled Mobile Robots With Multiple Driving Modes

Wheeled mobile robots (WMRs) are being used in many real-world applications. The main challenge in deployment of WMRs is their limited battery power. In order to complete a given task autonomously, it becomes necessary to estimate a priori the total energy consumption for the task assigned to a WMR. An accurate power consumption model allows to estimate the energy consumption of a WMR. This paper presents the power consumption modeling of WMRs using a power-based graphical modeling tool called bond graph. First, the dynamic bond graph model is developed for the generalized configuration of a WMR according to number and types of wheels attached in chassis. Then, the developed bond graph model is utilized for the power consumption modeling of a WMR. The proposed power consumption model includes the various driving modes of a WMR, by considering its degree of steerability. Finally, the proposed methodology is applied to a reconfigurable outdoor WMR with a degree of steerability varying from 0 to 2. The estimated power from the model is compared with the measured power from the experiments. Further, the proposed power model is used for the energy planning in a trajectory tracking task based on changing driving modes of a reconfigurable WMR.

The Development Strategy of Tourist Attraction in Taman Ayun Temple, Badung, Bali

This research aims to develop tourism that is friendly to culture and the environment through the concept of special interest tourism so that tourist attractions remain sustainable and have a positive impact on the welfare and happiness of the community. This research begins with identifying tourism, especially at Taman Ayun Temple, Badung Bali. This study uses qualitative methods, data collection is done by observation, interviews, document studies, and questionnaires. The results of the study indicate that there are internal factors that can influence the development of cultural festivals as a special interest tourist attraction at Taman Ayun Temple, namely professional staff. A strategic location is in the tourist attraction area of Taman Ayun Temple, while the external factor, which is the main weakness, is that the community is not aware of tourism, and the external factor, which is the main threat, is that there is no cultural festival tour package as a destination. The main opportunity is good road access that can be passed by various types of land transportation. The overall qualitative study shows that there is a great opportunity to develop a cultural festival that is used to attract tourism interest at Taman Ayun Temple, namely by opening good road access that can be passed by various types of land transportation wheels, which easily makes tourists feel comfortable and calm in making tourism trips.

WeMo: A Prototype of a Wearable Mobility Device Adapting to User's Natural Posture Changes.

Mobility is fundamental for human beings. In the current society, many personal mobility solutions have been invented to enable more time-efficient mobility, such as self-balancing vehicles, electric unicycles, and electric scooters. Personal mobility devices can provide flexibility to transportation. However, most personal mobility devices need to be carried by their users in the case that they climb stairs and steps. Therefore, many researchers have focused on developing stair-climbing vehicles, but due to the complicated mechanism, these devices are usually huge and heavy. To realize a new type of personal mobility device with more flexibility, we proposed a novel concept of a personal mobility device design that combines the agile mobility of a wheel type mechanism but does not limit a human's natural stair climbing ability. In this study, we introduced a compact personal mobility device, namely WeMo, under the concept of "wearing mobility", which extends humans' mobility in daily life. The developed hardware realizes "walking mode" and "driving mode". Users can move with the motorized driven wheels of the device during driving mode, and users can walk on their feet without any interference from the device during walking mode. In this manuscript, the detailed design of the hardware and control strategy were explained first.Then, we conducted fundamental user tests and discussed the ability of the developed device from test results. Finally, the conclusions and future work were provided.

玉米免耕机播种单体防黏土改进设计与试验

When the seeding monomer of no-tillage maize planter operates in sticky and wet soil, soil bonding and blocking of soil-touching parts will occur to different degrees, leading to functional failure and affecting the quality of seeding operation. Aiming to improve the anti-adhesion property with minimum cost, a seeding monomer is modified to operate in sticky and wet soil with the support of TRIZ (Theory of Inventive Problem Solving). There are two major scheme adjustments, including self-cleaning seedbed collating device and split gauge wheel. The Su-field model of seedbed collating device is constructed, and the design scheme of smaller wavy coulter and dirt scraper is proposed on the basis of the standard-solution tool and water-film theory. And the parameters of the wave are determined on account of force analysis of soil particles and bionic earthworm. Based on the systemic-functional analysis of the seeding depth-limiting device and the force analysis of gauge wheel during operation, a split type of depth-gauge wheel with large lug hole is designed. As a result, the field trial demonstrates that the improved monomer could meet the operation requirements of clay soil with the water content of 15%-25%. Compared with the original model, the residual clay content is decreased (seedbed collating device 57.5%, gauge wheel seeding depth-limiting device 10%). This study can provide reference for the anti-adhesion design of soil-contacting parts of agricultural machinery.

不同镇压方式对荞麦生长特性影响的试验研究

In order to fully explore the influence of different pressure methods on the growth characteristics of buckwheat, a pressure test device with adjustable press force, and easy to replace the press wheel was designed. Using the dry matter quality of buckwheat roots, stems, leaves at seedling stage, plant height, number of main stem nodes, number of main stem branches, grain number per plant, grain weight per plant, and yield as evaluation indexes, single factor test on press force was carried out, and three-factor and three-level orthogonal test was carried out too with press wheel outer diameter, press force and press wheel type as factors. The results showed that the index values of buckwheat showed a trend of first increasing and then decreasing with the increase of press force. When the press force was 450 N, the growth and development of buckwheat performed best. The effects of press wheel outer diameter, press force, and press wheel type on growth characteristics of buckwheat was different. The effects of press force and press wheel type on the indexes were greater than that of press wheel outer diameter. The optimal pressure methods of buckwheat sowing are as follows: the press wheel outer diameter is 300 mm, the press force is 450 N, and the press wheel type is conical combined wheel. The results of this study could provide reference for the improvement of high-yield mechanized sowing technology of buckwheat and the design of rational pressure device.

Fatigue life optimization and lightweight design of wheel based on entropy weight grey relation analysis and modified NSGA-II

In order to study the fatigue performance of wheel and enhance its lightweight design level, this article proposes the structure, design and optimization method of magnesium-aluminum alloy assembled wheel. Taking a [Formula: see text] type wheel as the research object, the optimal topology of wheel spoke is solved by constructing a topology optimization model for wheel bending and radial fatigue test conditions. A finite element model for bending and radial fatigue testing of assembled wheels was established, which simulates and analyzes the fatigue performance and its influencing factors of the wheel under two working conditions. Combined with contribution analysis method, the modified NSGA-II and entropy weight grey relation analysis (EGRA), the multi-objective optimization of assembled wheel was performed. The result demonstrated that the weight reduction of the assembled wheel after optimized design is 4.49%, while the bending fatigue life and radial fatigue safety factor are decreased by 9.95% and 25%, respectively. In order to better balance the performance of assembled wheel and achieve lightweight design, this article combines the joint topology optimization of assembled wheels with multi-objective optimization method for multiple working conditions and screens the optimal compromise solution by EGRA, which provides an approach for wheel lightweight design and multi-objective optimization.

Adaptive ultrasonic rail wheel testing system with advanced phased array technology

Non-destructive wheel inspection by means of ultrasound testing (UT) is crucial for highspeed, local or cargo trains. Any failure can lead to catastrophic events resulting in high material damage and personal injury or even fatalities. However, the inspection of train wheels is complicated due to different defect positions, which are to some part difficult to access, and a large variety of wheel geometries which are, moreover, influenced by the milage of the wheels. This article describes an industrial solution for the full-body inspection of train wheels including face, flange, web and tread. To cope with the high complexity of the inspection task, the Krautkrämer WheelStar implements advanced UT technologies in combination with a high automatization level and user-friendly controlling and inspection tools. In the first part of this article, general probe configurations and the benefits of Phased Array Ultrasonic Testing (PAUT), in particular the use of matrix probes, will be discussed. Afterwards, setup and evaluation software of the testing machine will be presented. The final part contains selected measurement results highlighting the testing capabilities. Comparative studies reveal the improvements of matrix probes. Moreover, it will be shown in which way these give access to new features such as a high precision coupling check or geometry measurements allowing a compensation of wheel wear or the identification of the wheel type (“smart probe”).

Phasor-Like Interpretation of the Angular Velocity of the Wheels of Omnidirectional Mobile Robots

Omnidirectionality is a feature that allows motion in any direction without orientation maneuvers. Omnidirectional mobile robots are usually based on omni or mecanum wheels. The motion of an omnidirectional mobile robot is defined by a target motion command M=v,α,ω, where v is the module of the translational velocity; α is the angular orientation of the translational velocity, and ω is the angular velocity of the mobile robot. The motion is achieved by converting the target motion command into the target angular velocities that must be applied to the active wheels of the robot. This work proposes a simplified phasor-like interpretation of the relationship between the parameters of a specific motion command and the angular velocities of the wheels. The concept of phasor-like notation is validated from the analysis of the kinematics of omnidirectional mobile robots using omni wheels and mecanum wheels. This simplified phasor-like notation fosters unconstrained conceptual design of single-type and hybrid multi-wheeled omnidirectional mobile robots without the distribution or type of wheels being a design constraint.

Actuator Materials for Environmentally Powered Engines

AbstractThe first solid‐state engine that converted heat into continuous mechanical motion using a thermally responsive actuating material was introduced almost a century ago. These engines used vulcanized rubber where the cyclically heating and cooling of the rubber generate continuous mechanical power in pendulum or wheel type engines. The development of solid‐state heat engines has seen several waves of activity with interest stimulated by the introduction of new actuating materials capable of responding to different environmental stimuli. Opportunities for improved engine outputs are afforded by recently developed artificial muscle materials. A theoretical connection between engine output and the characteristics of the actuator material is developed to compare the performances of vulcanized rubber, shape memory alloys (SMAs), and twisted and coiled polymer (TCP) fiber artificial muscles. It is shown that with an engine designed to suit the actuation performance of TCPs engines powered by the tensile actuation of such materials would exceed the output of SMA heat engines. The properties needed in actuator materials to further enhance engine output are identified and polymer structures that may produce such properties are described.