Xiuxia Yang

Impedance Control of Exoskeleton Suit Based on Adaptive RBF Neural Network

Abstract—Exoskeleton suit is a typical human-machine system. Control the exoskeleton suit to track the pilot’s moving trajectory as well as to minimize the human-machine interaction force. The suit will help decrease the pilot’s power consumption and assist the pilot to carry heavy load. Impedance control was introduced to the control of exoskeleton suit. As the control laws that based on the dynamic model without model uncertainty compensation will increase the human-machine force, a RBF neural network with adaptive learning algorithm was used to compensate the model uncertainty. The stability analysis of the control law was given and the simulation results show the feasibility and validity of the proposed control law.

Simulation research of exoskeleton suit based on Neural Network Sensitivity Amplification Control

Traditional exoskeleton suit need to install many complex sensors between the pilot and the exoskeleton system to measure the human-machine interactive information, which decrease the comfort of the pilot. Sensitivity amplification control can control the exoskeleton suit to trace the pilotpsilas movement as well as need no sensors between the pilot and the exoskeleton. However, sensitivity amplification control seriously relies on the systempsilas dynamic model and it is hard to build the exoskeleton suitpsilas dynamic model exactly because the exoskeleton suit is a multi-body, multi-degree and nonlinear system. So the dynamic model of the swing leg of exoskeleton suit was identified by BP neural networks, which simplified the procedure of building the system model. Neural network sensitivity amplification control was proposed and its feasibility was validated by simulation based on Simulink and SimMechanics toolbox in Matlab.

Simulation Research of Exoskeleton Suit Based on Sensitivity Amplification Control

Exoskeleton suit is a kind of human-machine robot, which combines the humans intelligence with the powerful energy of mechanism. It can help people to carry heavy load, walking on kinds of terrains and have a broadly apply area. Though many exoskeleton suits has been developed, there need many complex sensors between the pilot and the exoskeleton system, which decrease the comfort of the pilot. Sensitivity amplification control (SAC) is a method applied in exoskeleton system without any sensors between the pilot and the exoskeleton. In this paper simulation research was made to verify the feasibility of SAC include a simple 1-dof model and a swing phase model of 3-dof. A PID controller was taken to describe the human-machine interface model. Simulation results show the human only need to exert a scale-down version torque compared with the actuator and decrease the power consumes of the pilot.

Human-machine intelligent robot system control based on study algorithm

Based on the human-machine intelligent robot system of lower extremity carrying exoskeleton, the new control method is provided, where the virtual torque control is improved. The exoskeleton model is built using SimMechanics in Matlab. The dynamics mathematics model is gotten by study the human walking to construct the controller. The controller in virtual torque control uses nonlinear direct force control while not PID control. The control law presented in this paper simplifies the controller design and not making use of any information about the operator or of any of the mechanical characteristics of the human-machine interface. The most important of this method is the mass properties need not be identified, which overcomes the maximum defect of the virtual torque control. Simulation results show the valid of the given method.

Lower Extreme Carrying Exoskeleton Robot Adative Control Using Wavelet Neural Networks

Using the wavelet neural networks, an adaptive control system, with two wavelet neural networks as controller and dynamics model identifier respectively, is developed for lower extreme carrying exoskeleton robot. Because the wavelet neural networks have the ability to approximate nonlinear functions and good advantage of time-frequency localization properties, this system can identify nonlinear system dynamic characters more precisely, and can map more complex control strategies. Results show that this control system is more effective than those based on normal controller, where the exoskeleton tracking precision is high and the operator feels very little torque.

Design and Control Technique Research of Exoskeleton Suit

Naval Aeronautical Engineering Institute Exoskeleton Suit (NAEIES) is a kind of human-machine robot which combines the humans intelligence with the powerful energy of mechanism. It can help people to carry heavy load, walking on kinds of terrains. A prototype of NAEIES is proposed in this paper. When human walking, his (her) forearm has a similar motion trajectory with knee joint. So the forearm motion is measured by a potentiometer as the control signal of the knee joint. The hip joint motion is realized by a gas spring. This is the simplest method to realize the motion of NAEIES. The principle of the method was illustrate in the paper and for the further study a control techniques based on the feedback of angle acceleration is proposed and simulated with the one-Dof and two-Dof model of NAEIES leg.

A kinematic equation and trajectory planning of flexible arm space robot

The researches of flexible arm space robot kinematics are less, so as the trajectory planning researches from the kinematics aspect, the reason is flexible arm elastic vibration which has infinite dimensional vibration modality turn the space robot system kinematics to very complex. This paper denotes the elastic variable of space robot flexible arms with the flexible arm link end deformation and deformation angle, overcome the difficulty which may be brought by infinite dimensional vibration modality variable of flexible arm in modeling system kinematics. The kinematic equation of flexible arm space robot which includes elastic variable is established in the form of generalized Jacobian matrix. Continuous trajectory planning algorithm of flexible arm space robot in inertial space reference system is designed based on the kinematic equation. The simulation shows that planned rotary movement law of space robot arm joints may compensate for the impact that vibration of space robot flexible links gives to the end position of space robot arms, and ensure the end of space robot arms along the expected trajectory.