Torque Delivery Research Articles

Enhancing UAV elevator actuator model using multibody dynamics simulation

This paper proposes an improved actuator system model for UAV elevators using multibody dynamics simulation. The multibody dynamics simulation employs the Simscape Multibody, module in MATLAB coupled with Simulink to model the servo and hinge moment calculation. The actuator system comprises an electrical servo and mechanical components, including arms, push rods, horns, and the elevator. The electrical servo is modeled using a PID controller and a simplified motor model. The multibody dynamics simulation is employed to capture the dynamics of the mechanical components, coupled with the electrical servo through torque delivery to the mechanical components. The simulation is applied to the elevator of a medium altitude long endurance (MALE) UAV with a Maximum Take Off Weight of 1300 Kg. Generating these quantities provide a benefit in capturing the operational envelope of the servo to be compared to its limitations. Given the features of this simulation, it is proposed to extend the research by integrating this method with flight dynamics simulation.

Evaluation of the transient performance of a two-stage hybrid boosting system for spark ignition engines

This paper investigates a two-stage hybrid boosting system aimed at minimizing the delay in torque delivery that commonly characterizes turbocharged engines. Turbo-lag, particularly at low loads, reduces drivability, making the vehicle less competitive in the market. However, turbocharging is currently a simple and effective way of achieving high levels of specific power and efficiency, making its application mandatory. Hybridizing the turbocharging system by integrating a conventional turbocharger with an electrically assisted compressor can offer a solution to mitigate turbo-lag. The high dynamic response of the e-compressor significantly reduces time-to-boost, thus improving the engine’s response to load changes. This work presents the hybrid configuration with reference to a specific experimental campaign conducted on the University of Genoa’s test bench for components of propulsion system. The main results are presented, focusing on the boost pressure dynamic response during transient operations, highlighting the system’s behavior in various conditions and the benefits obtained by adopting an e-compressor in terms of time-to-boost. Furthermore, the experimental tests allow for the evaluation of the e-compressor electric power consumption under different operating conditions. The experimental results are then used as a reference to build a 1D model in GT-Power, reducing costs and time related to the experimental campaign while validating the data measured on the test bench.

Neuromechanical Model-Based Corrective Torque Estimation During Weight Shifting in Lower Limb Amputees

As a consequence of limb loss, unilateral lower limb amputees (LLAs) exert additional flexion torque in the intact limb during postural balance, leading to other secondary complications. A prosthetic device with torque delivery is required to avoid such complications. However, estimating desired torque is an acknowledged challenge in this domain. Motivated by the above, this paper focuses on estimating the corrective torque required from an assistive device to balance the individual while performing weight-shifting exercises. Further, a healthy individual’s inverted pendulum (IP) model is explored to model LLA’s dynamics during weight-shifting. The model and the control strategy are validated using forward and backward body lean angles recorded from healthy and LLA individuals. Finally, a robust Proportional Integral Derivative controller is designed to estimate the corrective torque for maintaining the postural balance during weight-shifting. Along with the IP dynamics, a suitable control law based on Coefficient Diagram Method achieves the experimentally recorded body lean angle. The proposed control scheme is validated through simulation studies to evaluate the tracking performance in two different biomechanically relevant IP postural models. The findings assist in determining the external torque required to maintain the postural balance during gait initiation and compensatory measures for pathologically reduced torque. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —Gait initiation is a transition between vertical posture and gait. Since vertical stance is inherently unstable, a postural adjustment occurs before gait initiates, propelling the center of mass forward and towards the first stance leg. The absence of flexor torque in the amputated limb causes a loss of postural stability during weight shifting activities. In the case of powered exoskeletons and prosthetic devices, a prior estimation of corrective torque through a computational approach helps to select a suitable actuator that provides an appropriate joint torque while maintaining the postural balance. As a result, an efficient computational model of gait initiation that accounts for neuromuscular system components before designing assistive devices is necessary. The controllers further provide corrective action to the assistive device to obtain robust and optimal coordination between the prosthetic element and gait. Therefore, this study demonstrates the significance of neuromuscular controller and assists in determining how much corrective torque from an external device is required to maintain postural stability and adaptability during weight shifting exercises. The effectiveness of the neural controller is also tested for real-time data to compensate for the effect of external disturbance and noise, thereby achieving a proper and controlled degree of movement in amputee users. These findings could provide one of the fundamental aspects of gait initiation model paradigms of compensatory measures for pathologically diminished torque and contribute to developing low-cost prosthetic solutions for the benefit of the rehabilitation society in developing countries.

Performance evaluation of a lowland cabbage harvester prototype

In Malaysia, round cabbage was planted in an area of 3,424 ha and 80,641 MT was produced in 2020. The shortage of workers is a major issue in large-scale cabbage cultivation. The most tedious and costly part was during the harvesting period since more workers were required. This article explained a modification and performance evaluation of a lowland cabbage harvester prototype. The prototype was designed and developed by MARDI in 2020. However, a few modifications were required to enhance the performance and efficiency of the developed prototype. A mechanism, which was called the reel system, was designed to ensure increased harvesting efficiency. The reel functioned as a puller mechanism to make sure the harvested cabbage was pulled smoothly to the conveyor system. The reel system also prevented the harvested cabbage from becoming stuck in the two cutting blades. It was driven by a 12V electric motor with 200W of power and connected to a gearbox, chain, and sprocket to increase the torque delivery. An evaluation performance test was carried out and the results showed that the effective field capacity was 0.065 ha/hr, with an average speed of 0.54 km/hr and 60.2% machine field efficiency. Only 14.4 man-hr/ha was required for the cabbage harvester while manual harvesting required 28.9 man-hr/ha. This represents a labour saving of about 50% when using the cabbage harvester.

Evolutionary Multiobjective Design Approach for Robust Balancing of the Shaking Force, Shaking Moment, and Torque under Uncertainties: Application to Robotic Manipulators

In this paper, the environmental uncertainties are taken into account when designing a robotic manipulator to balance the shaking force, shaking moment, and torque. The proposed robust balancing design approach does not consider the probability distributions of the uncertainties and is addressed without dependence on specific trajectories. This is expressed as a nonlinear constrained multiobjective optimization problem in which the nominal performance in the time-independent terms of the shaking force balancing, the shaking moment balancing, and the torque delivery, as well as their three sensitivities to uncertainties, are simultaneously optimized to provide a set of link shapes that match link mass distributions in a single stage. The proposal is applied to a three-degree-of-freedom serial-parallel manipulator, and the Non-Dominated Sorting Genetic Algorithm II (NSGA-II) is used to solve the associated problem. Comparative results with other design approaches reveal that the selected design achieves a suitable tradeoff in balancing the shaking force balancing, the shaking moment balancing, and the torque delivery and their sensitivities, leading to a reduction in their values and variations under mass changes in the manipulator end-effector with different operating conditions (tasks).

Real-time predictive clunk control using a reference governor

Backlash in the gears of an automotive drivetrain causes an unacceptable NVH phenomenon during torque delivery, called clunk, which adversely affects the drivability of a vehicle. Torque shaping control systems can help mitigate clunk but they may cause the vehicle to feel sluggish due to their conservative torque delivery during lash crossing and may be difficult to calibrate well for all use cases. In this work, we propose a novel, real-time predictive clunk controller using a soft landing reference governor approach, which helps in reducing clunk during lash crossing while simultaneously ensuring quick torque delivery. This model-based controller is easy to calibrate, and implemented in tandem with a shuffle controller and a backlash position estimator for providing smooth torque delivery during tip-in scenarios. Experimental data is used for developing a model, and the performance of the designed controller is verified through the experimentally validated model to meet impact velocity constraints in various use cases. Real-time capability of the controller is validated up to a sample time of 5 ms through processor-in-the-loop tests. The performance of the proposed controller is compared to a state-of-the-art model predictive clunk controller and to a conventional bang–bang clunk controller, and the benefit of using the reference governor-based clunk controller is demonstrated. The impact of model uncertainties on the performance of the clunk controller is analyzed and solutions for adapting to the uncertainties are demonstrated. Finally, the robustness of the controller is analyzed for various driver requested torque ramp rates and changes in the backlash size.

Optimizing Torque Delivery for an Energy-Limited Electric Race Car Using Model Predictive Control

This paper presents a torque controller for the energy optimization of the powertrain of an electric Formula Student race car. Limited battery capacity within electric race car designs requires energy management solutions to minimize lap time while simultaneously controlling and managing the overall energy consumption to finish the race. The energy-managing torque control algorithm developed in this work optimizes the finite onboard energy from the battery pack to reduce lap time and energy consumption when energy deficits occur. The longitudinal dynamics of the vehicle were represented by a linearized first-principles model and validated against a parameterized electric Formula Student race car model in commercial lap time simulation software. A Simulink-based model predictive controller (MPC) architecture was created to balance energy use requirements with optimum lap time. This controller was tested against a hardware-limited and torque-limited system in a constant torque request and a varying torque request scenario. The controller decreased the elapsed time to complete a 150 m straight-line acceleration by 11.4% over the torque-limited solution and 13.5% in a 150 m Formula Student manoeuvre.

Development of a hybrid racing car model and optimization of the torque delivery strategy by means of genetic algorithms

This paper proposes an optimization of torque strategy of All Wheel Drive hybrid vehicle taking part to Le Mans Hypercar championship. Using the software VI-Grade CarRealTime an existing reference model has been considered, and new co-simulated model with CarRealTime and Simulink with custom torque distribution has been defined. Subsequently, a simpler vehicle model has been developed only in Simulink to speed up the optimization problem, while conserving the same torque strategy of the co-simulated model. Regarding the optimization problem, two analysis are proposed. The first one is based on single-objective optimization that reduces the fuel consumption, by optimizing the use of the electric powertrain along the track; the second one is a multi-objective optimization that minimizes the fuel consumption and variation of State of Charge (SoC) using the same decision variable of single-objective optimization. The same penalty function is adopted in both cases to have a final SoC equal to the initial one. This analysis allow to design the size of battery and fuel tank as low as possible.

Structural Design and Friction Performance Test of a New Conical Groove Friction Disks in Wet Clutch

Wet clutch transmits its power by the friction torque between friction and separate disks. Conical groove friction disk is a new attempt in Wet clutch. Its configurations allow significant enhancement of torque delivery performances, compared with the traditional plane friction disk. In order to study the frictional performances of the conical groove friction configuration, the friction coefficient calculation model of conical groove friction disk was established, and experimental investigation was used to measure the friction coefficient under sliding velocity conditions. The influence of configuration parameters: cone heights and angles on friction coefficients were evaluated in a typical variable speed test. The results indicated that configuration parameters can affect friction performance in a constant speed period. The equivalent radius can directly describe the friction region of a conical groove friction disk. The constant speed test can be a useful method.

Development of Online Adaptive Traction Control for Electric Robotic Tractors

Estimation and control of wheel slip is a critical consideration in preventing loss of traction, minimizing power consumptions, and reducing soil disturbance. An approach to wheel slip estimation and control, which is robust to sensor noises and modeling imperfection, has been investigated in this study. The proposed method uses a simplified form of wheels longitudinal dynamic and the measurement of wheel and vehicle speeds to estimate and control the optimum slip. The longitudinal wheel forces were estimated using a robust sliding mode observer. A straightforward and simple interpolation method, which involves the use of Burckhardt tire model, instantaneous values of wheel slip, and the estimate of longitudinal force, was used to determine the optimum slip ratio that guarantees maximum friction coefficient between the wheel and the road surface. An integral sliding mode control strategy was also developed to force the wheel slip to track the desired optimum value. The algorithm was tested in Matlab/Simulink environment and later implemented on an autonomous electric vehicle test platform developed by the Nanjing agricultural university. Results from simulation and field tests on surfaces with different friction coefficients (μ) have proved that the algorithm can detect an abrupt change in terrain friction coefficient; it can also estimate and track the optimum slip. More so, the result has shown that the algorithm is robust to bounded variations on the weight on the wheels and rolling resistance. During simulation and field test, the system reduced the slip from non-optimal values of about 0.8 to optimal values of less than 0.2. The algorithm achieved a reduction in slip ratio by reducing the torque delivery to the wheel, which invariably leads to a reduction in wheel velocity.

Model Predictive Control of an Automotive Driveline for Optimal Torque Delivery with Minimal Oscillations during Torque Converter Slipping Conditions

Model Predictive Control of an Automotive Driveline for Optimal Torque Delivery with Minimal Oscillations during Torque Converter Slipping Conditions

Controls and Hardware Development of Multi-Level Miller Cycle Dynamic Skip Fire (mDSF) Technology

&lt;div class="section abstract"&gt;&lt;div class="htmlview paragraph"&gt;mDSF is a novel cylinder deactivation technology developed at Tula Technology, which combines the torque control of Dynamic Skip Fire (DSF) with Miller cycle engines to optimize fuel efficiency at minimal cost. mDSF employs a valvetrain with variable valve lift plus deactivation and novel control algorithms founded on Tula’s proven DSF technology. This allows cylinders to dynamically alternate among 3 potential states designated as: High Fire, Low Fire, and Skip (deactivation). The Low Fire state is achieved through an aggressive Miller cycle with Early Intake Valve Closing (EIVC). The three operating states in mDSF can be used to simultaneously optimize engine efficiency and driveline vibrations. Acceleration performance is retained using the all-cylinder, High Fire mode. mDSF can be implemented cost-effectively using an asymmetric intake valve lift strategy, with one high-flow power charging port and one high-efficiency Miller port.&lt;/div&gt;&lt;div class="htmlview paragraph"&gt;Prototype mDSF cylinder heads were based on the EA888 Gen 3B engine by retrofitting the valvetrain with asymmetric intake cams, deactivatable roller finger followers and two oil control valves per cylinder. Event-based engine controls were developed to enable for each cylinder dynamic selection of the three mDSF operating modes: High Fire, Low Fire and Skip. Appropriate air estimation, fuel control and ignition control techniques were employed to ensure acceptable torque delivery and tailpipe emissions.&lt;/div&gt;&lt;div class="htmlview paragraph"&gt;Engine dynamometer tests showed a 23% reduction in engine fuel consumption at 1500 rpm, 2 bar NMEP. Maximum torque and power from the baseline production engine up to 5000 rpm were also achieved. mDSF vehicle tests on the WLTC demonstrated a 6% reduction in CO&lt;sub&gt;2&lt;/sub&gt; from Miller 2-step. Euro 6d compliant emissions were also reported. Further improvements in fuel economy, drivability and NVH may be possible by leveraging mixed firing densities more extensively.&lt;/div&gt;&lt;/div&gt;

Current Ripple Minimisation in Deadbeat Parameter-Free Predictive Control of Synchronous Motor Drives

This paper proposes a motor parameter-free predictive current control of synchronous motor drives. In the context of motor parameter-free controls, the distinctive feature proposed in this paper is the use of the discrete space vector modulation technique. The advantages of the proposed architecture are manifold. As a distinctive feature of the proposed control algorithm compared to model-based solutions, is the real-time self-adaptation capability to the installed motor. Two recursive least-square estimators update runtime an accurate non parametric model. Compared to previous parameter-free solutions, the proposed algorithm can achieve a significantly lower current harmonic distortion at the same control frequency, while keeping the switching frequency value at bay. The result is an efficient and smooth torque delivery. The paper gives the necessary design hints and analyses the steady state performance in terms of both current harmonic distortion and switching frequency, taking finite-set model-based and parameter-free schemes as benchmark. This analysis was previously missing in literature for parameter-free schemes. Experimental validation is completed by including dynamic test results.

Direct Torque Model Predictive Control of a Five-Phase Permanent Magnet Synchronous Motor

Polyphase permanent magnet synchronous motors exhibit outstanding advantages over the traditional three-phase traction motors in electrified transportation applications. This article introduces a novel direct torque model predictive control technique aiming at developing a highly reliable, loss-minimizing, and energy-efficient five-phase permanent magnet synchronous motor drive. Leveraging the underlying constrained optimization process, the direct torque model predictive control approach optimizes the torque delivery and speed regulation quality, improves the flux and torque ripples, reduces higher order current harmonics, minimizes motor drive losses, and boosts power efficiency of the electric powertrain. dSPACE DS1104 hardware-in-the-loop and computer simulation studies are jointly utilized to verify the effectiveness and robustness of the proposed direct torque model predictive control approach in polyphase permanent magnet synchronous motor drive applications.

ВЛИЯНИЕ ДАВЛЕНИЯ РАЗРЯДКИ ГИДРОАККУМУЛЯТОРА НА ПРОЦЕСС ПЕРЕКЛЮЧЕНИЯ ПЕРЕДАЧ В КОРОБКАХ ПЕРЕДАЧ С ГИДРОУПРАВЛЕНИЕМ

The purpose of the study is the reduction of the time of hydraulic couplings slipping by optimization of hydraulic accumulator discharge pressure. When operating tractors with hydroshift transmission at loads close to the nomi-nal values, there is a problem of slipping of the friction coupling during gear shift without interruption in torque de-livery. There is a critical scientific problem of reducing the slipping of hydroshift transmission during the operation of major tractors. Theoretical prerequisites for increasing friction force due to the reduction of slipping via the re-duction of gear shift time and influence of oil pressure in the booster of the released drive are justified. Procedure and results of study of gear shift in transmission of tractor «Kirovets» with the use of both standard and constant discharge pressure hydraulic accumulators are given. The process of gear shift was investigated on the new gear-box with standard hydraulic accumulator, on the box with standard hydraulic accumulator worn to the limit provided, and on the new gearbox with constant discharge pressure hydraulic accumulator. It has been established that dur-ing operation of a new transmission with standard hydraulic accumulator the 0.2MPa discharge pressure exceeds the optimal value, which leads to an increase in the duration of the shift from 0.915...0.920 s at a pressure of 0.45...0.46 MPa to 1.395...1.04 s at a pressure of 0.65...0.66 MPa. The installation of a constant discharge pressure hydraulic accumulator on the new transmission reduces the discharge pressure to 0.48...0.49 MPa, which reduces the gear shift process to 1.034...1.040 s, that is only 4.2...6.6% higher than the optimal value. Recommendations are given to optimize the gear shift process in the transmission of the «Kirovets» tractor.

Validating implant torque limiting devices with a custom tool: A dental technique

The dental torque limiting device is a tool used to deliver a measured torque to implants and to their associated components. The torque delivery must be accurate and precise, especially when considering screw joints. Similar torque wrenches are used in various industries, and recommendations on calibration are provided by the International Organization for Standardization 6789-2:2017. It states that hand torque tools should be calibrated annually or more frequently if subjected to extreme temperature conditions such as steam sterilization. The International Organization for Standardization standard recommends that calibration may be performed by direct comparison of 2 torque devices provided that 1 is known to be within calibration. This technique article describes the procedures for fabricating a tool that couples 2 dental torque limiting devices. It may be used for calibrating and validating both electrical and mechanical torque limiting devices.

Automated engine calibration validation for real world driving conditions

With the introduction of the WLTP and RDE tests, it has become imperative for automotive manufacturers to verify that their vehicles operate reliably and efficiently across a wide range of operating conditions. Engine air-charge control and torque delivery should be consistent, smooth, and predictable, despite disturbances induced by technologies such as variable cam timing (VCT), exhaust gas recirculation (EGR) and forced induction. This is of particular importance to hybrid and ADAS-enabled vehicles which require accurate control of the engine torque. The validation is an iterative process which can be very time-consuming, expensive and requires considerable experience in order to meet validation criteria. This paper describes the introduction of an automated validation process at the Ford's Dunton Technical Centre in the UK. The automated procedure has been shown to reduce validation process time by around 50% resulting in significant cost-saving whilst improving the overall accuracy of the calibration by around 30-50%.

Automated engine calibration validation for real world driving conditions

With the introduction of the WLTP and RDE tests, it has become imperative for automotive manufacturers to verify that their vehicles operate reliably and efficiently across a wide range of operating conditions. Engine air-charge control and torque delivery should be consistent, smooth, and predictable, despite disturbances induced by technologies such as variable cam timing (VCT), exhaust gas recirculation (EGR) and forced induction. This is of particular importance to hybrid and ADAS-enabled vehicles which require accurate control of the engine torque. The validation is an iterative process which can be very time-consuming, expensive and requires considerable experience in order to meet validation criteria. This paper describes the introduction of an automated validation process at the Ford's Dunton Technical Centre in the UK. The automated procedure has been shown to reduce validation process time by around 50% resulting in significant cost-saving whilst improving the overall accuracy of the calibration by around 30-50%.

Design and Control of a Series Elastic Actuator With Clutch for Hip Exoskeleton for Precise Assistive Magnitude and Timing Control and Improved Mechanical Safety

Transparency and guaranteed safety are important requirements in the design of wearable exoskeleton actuators for individuals who have lower limb deficits but still maintain a certain level of voluntary motor control. Specifically, precision in torque delivery timing and magnitude, robustness, disturbance rejection, and repeatability are desired in the actuator design and control. Motivated by these needs, this study aims to develop a series of elastic actuators with clutch (SEAC) that can precisely generate the desired assistance in terms of both timing and torque magnitude for a wearable hip exoskeleton and guarantee the wearer's safety at the same time. The proposed mechanical design improves actuator transparency and safety by a mechanical clutch that automatically disengages the transmission when needed. A new torque control for the SEAC, based on singular perturbation theory with flexible compensation techniques, is proposed to precisely control the assistive torque by rejecting the undesired human motion disturbance. The mechanical design of the proposed device and the design of a singular perturbation control algorithm are discussed, and the SEAC performance is verified by experiments. Experimental results, derived from a test with a human subject, are presented to demonstrate the precision of the assistive torque and timing control of the SEAC while interacting with a human wearer.

Interconnection and Damping Assignment Passivity-Based Impedance Control of a Compliant Assistive Robot for Physical Human–Robot Interactions

Interest in series elastic actuators (SEAs) for assistive robots has recently increased due to the unique properties of SEAs compared to those of rigid actuators, such as high force control accuracy, low output impedance, and tolerance to shocks. In this letter, an SEA with a clutch for an assistive robot is designed for accurate torque delivery to provide effective assistance. The mechanical clutch controls the engagement and disengagement of the power transmission during the gait cycle to ensure transparency and user safety. Precise torque control is the main challenge in the control of SEAs. The addition of a clutch in the SEA will result in a new force control challenge with the frequent release and engagement of the clutch aggravating the mechanical vibration and bringing the risk of unsafety to the assistive robot wearer. A new torque control method based on interconnection and damping assignment passivity-based control (IDA-PBC) for SEAs is adopted for the physical human–robot interaction. Experiments are conducted to verify that the IDA-PBC-based SEA torque controller can effectively control actuator timing and allow precise assistive torque control. This letter serves as a stepping stone toward utilizing and designing assistive robots to assist with walking.