Tham khảo tài liệu 'sensors, focus on tactile, force and stress sensors 2011 part 7', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Study on Dynamic Characteristics of Six-axis Wrist Force torque Sensor 171 Fig. 4-1 Design schematic of dynamic compensating device by FLANN Where Wt are the weights of the network . the model coefficients of the dynamic compensation device k is the point number of data. The error is e k u k - u k The weight updating equations are given by Wn k 1 Wn k ae k y k - n n 0 1 2 Wm 2 k 1 Wm 2 k ae k u k - m - 2 m 1 2 where the learning constant a governs the stability and the rate of convergence. If the value of a is too small the speed of convergence is slow. If the value of a is too large the result may diverge. Generally speaking the value of a varies from 0 to 1. The simulation results show that it is suitable to set a about for our case. After training of many times when the average mean square error attains a minimum value the obtained weights are the coefficients of the compensation device. At the beginning of the on-line compensation we suppose u k y k where k 0 1 2 and u k is replaced by the output feedback u k . The equation of dynamic compensating is u k W0y k Wy k -1 W2y k - 2 W3u k -1 W4u k - 2 k 3 It should be noted that the designing equations mentioned above are used for one channel of the wrist force sensor and the equations for other channels are on the analogy of the above equations. Design procedure of dynamic compensation device 1. An ideal equivalent measurement system including the sensor and the dynamic compensation device is constructed by adjustment the damp ratio and natural frequency. 2. The exciting signal constructed or practical is inputted and the dynamic response of the equivalent measurement system is obtained. 3. Based on the dynamic responses of both the wrist force sensor and the equivalent measurement system a dynamic compensation device is designed. 172 Sensors Focus on Tactile Force and Stress Sensors 4. The dynamic response of the wrist force sensor is corrected. 5. In the light of the effects of .
