Development And Key Technology Research Of A Hybrid Force Feedback Device

Force feedback technology has been considered as an important human-computer interaction(HCI)approach and plays a vital role in the fields of virtual assembly,computer assisted medical surgery,and space teleoperation,etc.With the force information,the operators can perceive force and hardness during HCI process.Thus,complex operations can be completed esaily,and decision-making judgments can be corrected in real-time under the guidance of force feedback.As the interface of HCI,the performance of the force feedback device directly affects the operator’s experience in the manipulating process and the smoothness of operations.Therefore,it is indispensable to study the force compensation approaches and interactive performance indexes of a force feedback device.Based on the force feedback device developed previously,a serial wrist posture acquisition system is developed in this study firstly,key technologies such as gravity compensation and feedback force error compensation methods are explored;Then,the key interactive performance indexes of the force feedback device are analyzed.Finally,a measurement system is set up to complete the verification experiments.The main research contents are listed as follows.(1)Design,modeling,and simulation analysis of the wrist posture mechanism and the force feedback device.According to the ergonomic indicators,a three-degree-of-freedom wrist posture mechanism and its signal acquisition system are designed to obtain the operator’s posture information.The kinematics and dynamics of the device are established,and the virtual prototype is built in ADAMS.Both theoretical calculation and simulation methods are adopted to verify the correctness of the kinematics and dynamics models,and torque consumption of the active joints in the dynamic formula is analyzed.(2)Force compensation methods to enhance the transparency of force-sensing are presented.Firstly,the active gravity compensation method based on static analysis is adopted to calculate the torque consumption.Then,to reduce the workload of the motors,a spring structure is introduced,and the particle swarm optimization algorithm(PSO)is adopted to optimize the spring structural parameters to achieve partial passive gravity compensation.Based on these,an active and passive combined gravity compensation approach is proposed.Besides,the feedback force error generation reasons of the force feedback device are summarized,and a feedforward feedback force error compensation method based on RBF neural network is proposed to improve the accuracy of the feedback output.(3)Key interactive performance indicators of the force feedback device are analyzed.Firstly,The output force capability is calculated when considering the effect of gravity compensation.Simulation experiments are conducted to verify the superiority of the active and passive combined gravity compensation approach.Then,based on the condition number of the Jacobian matrix and dexterity of the device,the global dexterity index is calculated and proved with favorable operability.(4)Verification of the performance of the proposed gravity compensation and feedback force error compensation methods is done.Firstly,an experimental measurement system is designed and set up.It is composed of a multi-degree-of-freedom motion module,a laptop,an intelligent display instrument,and a force sensor.Then,experiments are conducted and results are discussed.The results demonstrate that the proposed force compensation method can compensate for the gravity of the device effectively and reduce the feedback force error,and the transparency of the output force of the device enhanced.