Hybrid Robotic System Research Articles

Analysis of the cognitive properties of neural systems based on biofeedback

Problems of cognitive system reengineering, i.e., the development of devices with cognitive properties on the basis of their biological prototypes, cannot be solved without understanding the basic features of the architecture of biological systems, information properties, and molecular organization of the primitive units forming the architecture: nerve cells. The construction of learning models makes it possible to study the activity of individual cells, not only in terms of behavioral responses to natural stimuli but also in experiments on isolated preparations with excitation of peripheral bodies and isolated cell structures. The software-tool complex NeuroFeedBack was developed; it includes a system of living neurons and a neurocomputer interface feedback. The complex provides the reception and processing of input signals from neurons, their visualization and storage, as well as the generation of output reinforcing stimuli applied to the neurons. Analysis of the functional activity of neurons of the right parietal ganglion of the Lymnaea stagnalis mollusk was performed with the complex in three models of reinforcement. It was shown that optimization of neural activity occurred under conditions of biofeedback, allowing the neuron to minimize the quantity of the reinforcing stimuli. The results provided grounds for the design of a hybrid robotic system in which living neural systems using a neurocomputer interface could solve navigation tasks, controlling a real-time mechanoelectronical device operating in a real environment. In the experiment, the use of the proposed programs of hybrid reinforcements allowed the robot to find a glowing light bulb and reach it in a few minutes.

Locomotion control of hybrid cockroach robots.

Natural systems retain significant advantages over engineered systems in many aspects, including size and versatility. In this research, we develop a hybrid robotic system using American (Periplaneta americana) and discoid (Blaberus discoidalis) cockroaches that uses the natural locomotion and robustness of the insect. A tethered control system was firstly characterized using American cockroaches, wherein implanted electrodes were used to apply an electrical stimulus to the prothoracic ganglia. Using this approach, larger discoid cockroaches were engineered into a remotely controlled hybrid robotic system. Locomotion control was achieved through electrical stimulation of the prothoracic ganglia, via a remotely operated backpack system and implanted electrodes. The backpack consisted of a microcontroller with integrated transceiver protocol, and a rechargeable battery. The hybrid discoid roach was able to walk, and turn in response to an electrical stimulus to its nervous system with high repeatability of 60%.

Towards a Robotic Knee Exoskeleton Control Based on Human Motion Intention through EEG and sEMGsignals

The integration of lower limb exoskeletons with robotic walkers allows obtaining a system to improve mobility and security during gait rehabilitation. In this work, the evaluation of human motion intention (HMI) based on electroencephalogram (EEG) and surface electromyography (sEMG) signals are analyzed for a knee exoskeleton control as a preliminary study for gait neuro-rehabilitation with a hybrid robotic system. This system consists of the knee exoskeleton H2 and the UFES's Smart Walker, which are used to restore the neuromotor control function of subjects with neural injuries. An experimental protocol was developed to identify patterns to control the exoskeleton in accordance with the HMI-based on EEG/sEMG. The EEG and sEMG signals are recorded during the following activities: stand-up/sit-down and knee flexion/extension. HMI is analyzed through both event-related desynchronization/synchronization (ERD/ERS) and slow cortical potential, as well as the myoelectric pattern classification related to lower limb. The feature extraction from sEMG signals is based on vector combinations in time and frequency domain which are used for a pattern classification stage trough an artificial neural network with Levenberg Marquadt training algorithm and support vector machine. Preliminary results shown that a combination of EEG/sEMG signals can be used to define a control strategy for the robotic system.

A Hybrid Combining Hard and Soft Robots

Abstract This article describes a hybrid robotic system combining hard and soft subsystems. This hybrid comprises a wheeled robot (an iRobot Create; hard) and a four-legged quadruped (soft). It is capable (using a simple, wireless control system) of rapid locomotion over flat terrain (using the wheeled hard robot) and of gripping and retrieving an object (using the independent locomotive capabilities of the soft robot). The utility of this system is demonstrated by performing a mission requiring the capabilities of both components: retrieving an object (iPod Nano) from the center of a room. This class of robot—hybrids comprising hard and soft systems functioning synergistically—is capable of performing tasks that neither can do alone. In contrast to specialized hard robotic arms with grippers (capable of performing some of the functions we describe here), which are complex, relatively expensive, and require sophisticated controls, this hybrid system is easy to construct, simple to control, and low in cost...

A Removable Hybrid Robot System for Long Bone Fracture Reduction

In traditional long bone fracture reduction surgery, there are some drawbacks such as low accuracy, high radiation for surgeons and a risk of infection. To overcome these disadvantages, a removable hybrid robot system is developed, which integrates a removable series-parallel mechanism with a motor-double cylinder (MDC) driven mode. This paper describes the mechanism in detail, analyses the principle and the method of the fracture reduction, presents the surgical procedure, and verifies the reduction accuracy by experiments with bone models. The results are shown as follows. The mean deviations of the axial displacement and lateral displacement are 1.60mm and 1.26 mm respectively. The standard deviations are 0.69 mm and 0.30 mm. The mean deviations of the side angle and turn inward are 2.06° and 2.22° respectively. The standard deviations are 0.50° and 0.99°. This minimally invasive robot features high accuracy and zero radiation for surgeons, and is able to conduct fracture reduction for long bones.

The mechanical forces in katydid sound production

Katydids and crickets generate their characteristic calling sound by rubbing their wings together. The mechanisms of the rubbing force, however, have not been extensively studied. The change of mechanical force with external parameters (speed and applied load) in the stridulation process has not been reported. Our current study aims to investigate the mechanical forces of katydid stridulation. Four pairs of files and plectrums from a katydid, which are responsible for the katydid's sound production, were examined with a specially designed experimental configuration. Due to the asymmetric nature of the wing motion in their opening and closing, the contact between the plectrum and file resembles that of a ratchet. Multiple frequencies were generated during experimental wing rubbing so that a calling-like sound was produced. Results showed that the morphology of the plectrum/file contact has significant effects on mechanical forces induced on the wings and resulting sound production. The roles of the mechanical forces include sound generation, tone modification, and energy consumption. The findings in this work reveal the variation trend of mechanical force with sliding speed and applied load. The frequency and amplitude of the sound wave produced in tribo-test are close to those in natural condition. By mimicking the microstructure of the plectrum and file teeth, acoustic instruments with high mechanical energy conversion rate can be developed. Our results provide new approaches in the design and improvement of micro-machines for acoustic applications, as well as in hybrid robotic systems.

Automation Highlights from the Literature

Automation Highlights from the Literature

A Simple and Novel Hybrid Robotic System for Robot-Assisted Femur Fracture Reduction

When performing femur fracture reduction surgery, both the patient and surgeon are exposed to a great amount of radiation, which is harmful to their health. In order to reduce such radiation from the usage of an image intensifier, various robots have been proposed for femur fracture reduction surgery. Most of these robots are based on serial architecture. The low transportable load and poor accuracy are both inherent in serial robots, which makes them inappropriate for femur fracture reduction. Some parallel robots based on the 'Stewart platform' have also been developed for femur fracture reduction, but their restricted workspace limits their applicability and accessibility. To balance the accuracy, payload and workspace, a new robot system is reported in this paper. The proposed robot system consists of a 2-d.o.f. device and a 6-d.o.f. hybrid robot. The 2-d.o.f. device is used for distraction, which requires a very large force. The hybrid robot is used to manipulate a bone fragment for alignment and fixation purposes. The hybrid robot possesses the characteristic of a Cartesian coordinate robot; all the movements of the actuators are linear, which makes its motion smooth for low-speed fracture reduction procedures. The forward and inverse kinematics of the proposed robot are analyzed. The analysis is much simpler compared to traditional serial manipulators and parallel Stewart platform robots. A prototype of the proposed system is made using a rapid fabrication system called Objet. The positioning accuracy of the proposed system is measured using a coordinate-measuring machine. The results show that the algorithms presented in this paper for the control of the robot are accurate and robust.

A vision guided hybrid robotic prototype system for stereotactic surgery

Robot-assisted surgery (RAS) systems help surgeons performing accurate operations, but a number of drawbacks render them not yet suitable for clinical theaters and procedures. In this paper, a novel vision guided robotic system is proposed to facilitate navigation procedures. A vision guided hybrid robotic system is designed, consisting of a passive serial arm and an active parallel frame. Navigation is accomplished in three steps: approaching, aiming and insertion. First, the target is safely approached with the passive arm. Second, the trajectory is automatically aligned using the parallel frame. And then the target is reached by manual insertion. A stereo camera is used to position fiducials, the robot and the surgical tool. It also provides working area images for professional surgeons at a remote site. The prototype system accomplished phantom and animal trials with satisfactory accuracy. The robot can easily be adjusted to avoid obstacles and quickly set up on an optimal 'approaching' place. The surgical tool is automatically aligned with the trajectory. The system can withdraw from the working area and restore the aiming posture freely. With the help of the working area images, some important navigation steps can be handled remotely. A novel vision guided robotic system is proposed and validated. It enables surgeons to fit the system to the clinical theater. System safety and feasibility are enhanced by multi-step navigation procedures and remote image monitoring. The system can be operated easily by general clinical staff.

Simultaneous Localization and Mapping in a Hybrid Robot and Camera Network System

To obtain accurate grid maps of large environments equipped with camera networks in real time, a two-level mapping method is presented in this paper. The local map level is composed of a set of local maps. Once a mobile robot enters a new camera visual field, a new local map corresponding to the camera is built by a Rao-Blackwellized particle filter (RBPF) method using the data from the robot’s laser sensor and odometry. During the local mapping process, a camera-calibration problem is also solved by using a marker attached to the robot which moves as a curve fashion in the camera visual field. The global level is an adjacency graph whose arcs are labeled with the relative transformations between local maps. Among these relative transformations, of particular important are the revisiting constraints. When the robot returns a previous local map, it can be detected and relocated by a calibrated camera corresponding to the local map. Then a revisiting constraint can be attained and added into global constraints. To have an accurate and consistent global map, a stochastic gradient descent (SGD) algorithm based on a simple state space is employed to optimize the existed graph after adding and updating each global constraint. Experimental results carried out with a real mobile robot in a large-scale indoor environment illustrate the advantages of our methods over two current state-of-the-art approaches.

Computed torque control of an under-actuated service robot platform modeled by natural coordinates

The paper investigates the motion planning of a suspended service robot platform equipped with ducted fan actuators. The platform consists of an RRT robot and a cable suspended swinging actuator that form a subsequent parallel kinematic chain and it is equipped with ducted fan actuators. In spite of the complementary ducted fan actuators, the system is under-actuated. The method of computed torques is applied to control the motion of the robot. The under-actuated systems have less control inputs than degrees of freedom. We assume that the investigated under-actuated system has desired outputs of the same number as inputs. In spite of the fact that the inverse dynamical calculation leads to the solution of a system of differential–algebraic equations (DAE), the desired control inputs can be determined uniquely by the method of computed torques. We use natural (Cartesian) coordinates to describe the configuration of the robot, while a set of algebraic equations represents the geometric constraints. In this modeling approach the mathematical model of the dynamical system itself is also a DAE. The paper discusses the inverse dynamics problem of the complex hybrid robotic system. The results include the desired actuator forces as well as the nominal coordinates corresponding to the desired motion of the carried payload. The method of computed torque control with a PD controller is applied to under-actuated systems described by natural coordinates, while the inverse dynamics is solved via the backward Euler discretization of the DAE system for which a general formalism is proposed. The results are compared with the closed form results obtained by simplified models of the system. Numerical simulation and experiments demonstrate the applicability of the presented concepts.

A hybrid robot system for CT-guided surgery

SUMMARYThe common serial robot or parallel robot is difficult to implement for CT-guided surgery in a limited workspace. A novel hybrid robot with 9 degrees of freedom is presented in this paper, whose detailed structure is analysed based on screw theory and displacement manifold (DM). The dexterity of the hybrid robot is provided in terms of Riemann manifold (RM). Besides, DICOM (digital imaging communications in medicine) image processing, spatial registration and 3D dynamic reconstruction in the operation planning subsystem are analysed, in which some innovative methods are introduced. Meanwhile, the architecture of the CT-guided hybrid robot system and its subsystems are proposed. Simulative clinical experiment showed that the locating precision of the hybrid robot reaches 1.08 mm, which can meet the requirement of CT-guided surgery.

Shared Potential Fields and their place in a multi-robot co-ordination taxonomy

Previously our novel Shared Potential Field (SPF) method has been introduced and compared against a non-sharing control in both simulation and laboratory settings. In this paper, extended from a paper presented at the CIRAS 2008 conference, we compare the SPF against an existing type of robot architecture, a hybrid robotic system. The SPF method is compared to the traditional potential field method, and it is shown that the SPF is less susceptible to the traditional limitations of potential fields. The SPF method’s position in Farinelli’s multi-robot taxonomy is also discussed, and it is shown that rather than being placed in one category it encompasses two, corresponding to the two levels of control within the architecture. In experiments, the multi-robot systems are given the task of traversing an unknown environment, in an attempt to locate a target. The metric of performance for this task was the time taken to find the target. Experiments show that the hybrid system showed similar performance to the non-sharing control. In contrast, our Pessimistic variant of the SPF outperformed the hybrid system in the cluttered environment, and the Optimistic SPF variant outperformed the hybrid system in the sparse environment. We conclude that the SPF method reacts more robustly to the dynamic nature of the real world, and so performed significantly better throughout the experimentation.

Performance Evaluation for Multi-arm Manipulation of Hollow Suspended Organs

This paper presents a unified mathematical framework for modeling and evaluating the performance of multiple robotic arms that operate on hollow suspended organs. This framework is applied to a novel two-armed hybrid robotic system being developed for ophthalmic vitreous surgeries. Four cases are designated to capture the general movements required for any surgical procedure associated with hollow suspended organs. Dexterity measures, based on multiple characteristic lengths, are presented for procedures corresponding to these manipulation cases. Simulation results of the dual-arm robotic system for ophthalmic surgery are presented for all four manipulation cases. A comparison of this robotic system with current surgical tools shows a significant improvement in intraocular dexterity.

A Hybrid Robot System Guided by Computer Tomography for Percutaneous Lung Cancer Cryosurgery

Using the common serial robot or parallel robot it is difficult to implement computed tomography (CT) guided surgery in a limited workspace. A novel hybrid robot with 9 d.o.f. is presented, the detailed structures of which are analyzed based on screw theory and the displacement manifold. The dexterity of the hybrid robot is provided in terms of the Riemann manifold. The structure of the control system is described. DICOM image processing, spatial registration and three-dimensional dynamic reconstruction in the operation planning subsystem are analyzed, using some new methods that are explained. The architecture of the CT-guided robot system and its subsystems is put forward. Simulative clinical experimentation shows that the locating precision of the hybrid robot is 1.08 mm, which can meet the requirements of clinical cryosurgery.

Hybrid systems: from verification to falsification by combining motion planning and discrete search

We propose HyDICE, Hybrid Discrete Continuous Exploration, a multi-layered approach for hybrid-system falsification that combines motion planning with discrete search and discovers safety violations by computing witness trajectories to unsafe states. The discrete search uses discrete transitions and a state-space decomposition to guide the motion planner during the search for witness trajectories. Experiments on a nonlinear hybrid robotic system with over one million modes and experiments with an aircraft conflict-resolution protocol with high-dimensional continuous state spaces demonstrate the effectiveness of HyDICE. Comparisons to related work show computational speedups of up to two orders of magnitude.

A Hybrid Robotic System for Harvesting Heavy Produce

Certain agricultural work requires a very stiff robot arm to reduce vibration and damage to products. However, the structure of conventional articulated robots tends to be too weak to manipulate heavy objects, such as melons and watermelons. The Stewart platform is a typical parallel robotic mechanism with very high stiffness, but this advantage is balanced by a small workspace and large installation space. This research proposes a new type of agricultural robot arm constructed by combining a parallel and a serial mechanism. This robot consists of a hybrid manipulator, a robot controller and an end-effector. The hybrid manipulator has serial joints with two extra degrees of freedom, making the workspace wider. It was also designed to harvest heavy fruits such as melons, even from behind obstacles such as leaves or tree branches. Position control results of the developed hybrid robot showed that it could be controlled within a ±1 mm and ±0.2° range of error.

A Hybrid Robotic System for Harvesting Heavy Produce

A Hybrid Robotic System for Harvesting Heavy Produce

Culture of insect cells contracting spontaneously; research moving toward an environmentally robust hybrid robotic system

Here we propose an environmentally robust hybrid (biotic–abiotic) robotic system that uses insect heart cells. Our group has already presented a hybrid actuator using rat heart muscle cells, but it is difficult to keep rat heart muscle cells contracting spontaneously without maintaining the culture conditions carefully. Insect cells, by contrast, are robust over a range of culture conditions (temperature, osmotic pressure and pH) compared to mammalian cells. Therefore, a hybrid robotic system using not mammalian cells but insect cells can be driven without precise environmental control. As a first step toward the realization of this robotic system, the larvae of two lepidopteran species, Bombyx mori (BM) and Thysanoplusia intermixta (TI) were excised and the culture conditions of their dorsal vessel (insect heart) cells were examined. As a result, spontaneously contracting TI cells derived from the dorsal vessel were obtained. The contraction of TI cells started on the 7th day and continued for more than 18 days. Spontaneously contracting BM cells were not obtained in this study. These experimental results suggest the possibility of constructing an environmentally robust hybrid robotic system with living cells in the near future.

Hybrid Robot System Fire-Defense in High-Rise Buildings

Due to the recent increase in the number of high-rise buildings, fire-defense is attracting much attention. When a fire occurs in a high-rise building, the area of firefighting is restricted because the ladder of a fire engine has a short reach. A solution to this problem lead is a hybrid robot. The robot maintains the building under normal conditions; and in case of a fire, it assists in fire-defense by replacing the Maintenance Unit with a Fire-Defense Assist Unit. The main characteristics of the robot are as follows. (1) It is possible to replace the Maintenance Unit with a Fire-defense Assist Unit. (2) It is possible to move horizontal along the surface of the building with guide rail. (3) It is possible to monitor rooms through glass by a device that consists of a CCD camera and an sinfrared imaging device. (4) It is possible to cut windows in building for Fire-defense Assist. A 3-year feasibility study of the robot since 1990 led to the fundamental design. Practical testing of a prototype model confirmed the validity of its several fundamental functions and performance.