Saba Zerefa
2.74 team project
Dependencies: ExperimentServer QEI_pmw MotorShield
Diff: main.cpp
- Revision:
- 1:25284247a74c
- Child:
- 2:4e581e5b39e8
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Mon Nov 22 07:41:36 2021 +0000
@@ -0,0 +1,405 @@
+#include "mbed.h"
+#include <stdio.h> /* printf */
+#include <math.h> /* cos */
+#include "rtos.h"
+#include "EthernetInterface.h"
+#include "ExperimentServer.h"
+#include "QEI.h"
+#include "BezierCurve.h"
+#include "MotorShield.h"
+#include "HardwareSetup.h"
+
+#define BEZIER_ORDER_FOOT 7
+#define NUM_INPUTS (12 + 2*(BEZIER_ORDER_FOOT+1))
+#define NUM_OUTPUTS 19
+
+#define PULSE_TO_RAD (2.0f*3.14159f / 1200.0f)
+
+// Initializations
+Serial pc(USBTX, USBRX); // USB Serial Terminal
+ExperimentServer server; // Object that lets us communicate with MATLAB
+Timer t; // Timer to measure elapsed time of experiment
+
+QEI encoderA(PE_9,PE_11, NC, 1200, QEI::X4_ENCODING); // MOTOR A ENCODER (no index, 1200 counts/rev, Quadrature encoding)
+QEI encoderB(PA_5, PB_3, NC, 1200, QEI::X4_ENCODING); // MOTOR B ENCODER (no index, 1200 counts/rev, Quadrature encoding)
+QEI encoderC(PC_6, PC_7, NC, 1200, QEI::X4_ENCODING); // MOTOR C ENCODER (no index, 1200 counts/rev, Quadrature encoding)
+QEI encoderD(PD_12, PD_13, NC, 1200, QEI::X4_ENCODING);// MOTOR D ENCODER (no index, 1200 counts/rev, Quadrature encoding)
+
+
+MotorShield motorShield(12000); //initialize the motor shield with a period of 12000 ticks or ~20kHZ
+Ticker currentLoop;
+
+// Variables for q1
+float current1;
+float current_des1 = 0;
+float prev_current_des1 = 0;
+float current_int1 = 0;
+float angle1;
+float velocity1;
+float duty_cycle1;
+float angle1_init;
+
+// Variables for q2
+float current2;
+float current_des2 = 0;
+float prev_current_des2 = 0;
+float current_int2 = 0;
+float angle2;
+float velocity2;
+float duty_cycle2;
+float angle2_init;
+
+// Fixed kinematic parameters
+const float l_OA=.011;
+const float l_OB=.042;
+const float l_AC=.096;
+const float l_DE=.091;
+
+// Timing parameters
+float current_control_period_us = 200.0f; // 5kHz current control loop
+float impedance_control_period_us = 1000.0f; // 1kHz impedance control loop
+float start_period, traj_period, end_period;
+
+// Control parameters
+float current_Kp = 4.0f;
+float current_Ki = 0.4f;
+float current_int_max = 3.0f;
+float duty_max;
+float K_xx;
+float K_yy;
+float K_xy;
+float D_xx;
+float D_xy;
+float D_yy;
+
+// Model parameters
+float supply_voltage = 12; // motor supply voltage
+float R = 2.0f; // motor resistance
+float k_t = 0.18f; // motor torque constant
+float nu = 0.0005; // motor viscous friction
+
+// Current control interrupt function
+void CurrentLoop()
+{
+ // This loop sets the motor voltage commands using PI current controllers with feedforward terms.
+
+ //use the motor shield as follows:
+ //motorShield.motorAWrite(DUTY CYCLE, DIRECTION), DIRECTION = 0 is forward, DIRECTION =1 is backwards.
+
+ current1 = -(((float(motorShield.readCurrentA())/65536.0f)*30.0f)-15.0f); // measure current
+ velocity1 = encoderA.getVelocity() * PULSE_TO_RAD; // measure velocity
+ float err_c1 = current_des1 - current1; // current errror
+ current_int1 += err_c1; // integrate error
+ current_int1 = fmaxf( fminf(current_int1, current_int_max), -current_int_max); // anti-windup
+ float ff1 = R*current_des1 + k_t*velocity1; // feedforward terms
+ duty_cycle1 = (ff1 + current_Kp*err_c1 + current_Ki*current_int1)/supply_voltage; // PI current controller
+
+ float absDuty1 = abs(duty_cycle1);
+ if (absDuty1 > duty_max) {
+ duty_cycle1 *= duty_max / absDuty1;
+ absDuty1 = duty_max;
+ }
+ if (duty_cycle1 < 0) { // backwards
+ motorShield.motorAWrite(absDuty1, 1);
+ } else { // forwards
+ motorShield.motorAWrite(absDuty1, 0);
+ }
+ prev_current_des1 = current_des1;
+
+ current2 = -(((float(motorShield.readCurrentB())/65536.0f)*30.0f)-15.0f); // measure current
+ velocity2 = encoderB.getVelocity() * PULSE_TO_RAD; // measure velocity
+ float err_c2 = current_des2 - current2; // current error
+ current_int2 += err_c2; // integrate error
+ current_int2 = fmaxf( fminf(current_int2, current_int_max), -current_int_max); // anti-windup
+ float ff2 = R*current_des2 + k_t*velocity2; // feedforward terms
+ duty_cycle2 = (ff2 + current_Kp*err_c2 + current_Ki*current_int2)/supply_voltage; // PI current controller
+
+ float absDuty2 = abs(duty_cycle2);
+ if (absDuty2 > duty_max) {
+ duty_cycle2 *= duty_max / absDuty2;
+ absDuty2 = duty_max;
+ }
+ if (duty_cycle2 < 0) { // backwards
+ motorShield.motorBWrite(absDuty2, 1);
+ } else { // forwards
+ motorShield.motorBWrite(absDuty2, 0);
+ }
+ prev_current_des2 = current_des2;
+
+
+ current3 = -(((float(motorShield.readCurrentA())/65536.0f)*30.0f)-15.0f); // measure current
+ velocity3 = encoderA.getVelocity() * PULSE_TO_RAD; // measure velocity
+ float err_c3 = current_des3 - current3; // current errror
+ current_int3 += err_c3; // integrate error
+ current_int3 = fmaxf( fminf(current_int3, current_int_max), -current_int_max); // anti-windup
+ float ff3 = R*current_des3 + k_t*velocity3; // feedforward terms
+ duty_cycle3 = (ff3 + current_Kp*err_c3 + current_Ki*current_int3)/supply_voltage; // PI current controller
+
+ float absDuty3 = abs(duty_cycle3);
+ if (absDuty3 > duty_max) {
+ duty_cycle3 *= duty_max / absDuty3;
+ absDuty3 = duty_max;
+ }
+ if (duty_cycle3 < 0) { // backwards
+ motorShield.motorCWrite(absDuty3, 1);
+ } else { // forwards
+ motorShield.motorCWrite(absDuty3, 0);
+ }
+ prev_current_des3 = current_des3;
+
+
+ current4 = -(((float(motorShield.readCurrentA())/65536.0f)*30.0f)-15.0f); // measure current
+ velocity4 = encoderA.getVelocity() * PULSE_TO_RAD; // measure velocity
+ float err_c4 = current_des4 - current4; // current errror
+ current_int4 += err_c4; // integrate error
+ current_int4 = fmaxf( fminf(current_int4, current_int_max), -current_int_max); // anti-windup
+ float ff4 = R*current_des4 + k_t*velocity4; // feedforward terms
+ duty_cycle4 = (ff4 + current_Kp*err_c4 + current_Ki*current_int4)/supply_voltage; // PI current controller
+
+ float absDuty4 = abs(duty_cycle4);
+ if (absDuty4 > duty_max) {
+ duty_cycle4 *= duty_max / absDuty4;
+ absDuty4 = duty_max;
+ }
+ if (duty_cycle4 < 0) { // backwards
+ motorShield.motorCWrite(absDuty4, 1);
+ } else { // forwards
+ motorShield.motorCWrite(absDuty4, 0);
+ }
+ prev_current_des4 = current_des4;
+
+
+}
+
+int main (void)
+{
+
+ // Object for 7th order Cartesian foot trajectory.
+
+ //CREATE A TRAJECTORY
+ BezierCurve rDesFoot_bez(2,BEZIER_ORDER_FOOT);
+
+ // Link the terminal with our server and start it up
+ server.attachTerminal(pc);
+ server.init();
+
+ // Continually get input from MATLAB and run experiments
+ float input_params[NUM_INPUTS];
+ pc.printf("%f",input_params[0]);
+
+ while(1) {
+
+ // If there are new inputs, this code will run
+ if (server.getParams(input_params,NUM_INPUTS)) {
+
+
+ // Get inputs from MATLAB
+ start_period = input_params[0]; // First buffer time, before trajectory
+ traj_period = input_params[1]; // Trajectory time/length
+ end_period = input_params[2]; // Second buffer time, after trajectory
+
+ angle1_init = input_params[3]; // Initial angle for q1 (rad)
+ angle2_init = input_params[4]; // Initial angle for q2 (rad)
+
+ K_xx = input_params[5]; // Foot stiffness N/m
+ K_yy = input_params[6]; // Foot stiffness N/m
+ K_xy = input_params[7]; // Foot stiffness N/m
+ D_xx = input_params[8]; // Foot damping N/(m/s)
+ D_yy = input_params[9]; // Foot damping N/(m/s)
+ D_xy = input_params[10]; // Foot damping N/(m/s)
+ duty_max = input_params[11]; // Maximum duty factor
+
+ // Get foot trajectory points
+ float foot_pts[2*(BEZIER_ORDER_FOOT+1)];
+ for(int i = 0; i<2*(BEZIER_ORDER_FOOT+1);i++) {
+ foot_pts[i] = input_params[12+i];
+ }
+ rDesFoot_bez.setPoints(foot_pts);
+
+ // Attach current loop interrupt
+ currentLoop.attach_us(CurrentLoop,current_control_period_us);
+
+ // Setup experiment
+ t.reset();
+ t.start();
+ encoderA.reset();
+ encoderB.reset();
+ encoderC.reset();
+ encoderD.reset();
+
+ motorShield.motorAWrite(0, 0); //turn motor A off
+ motorShield.motorBWrite(0, 0); //turn motor B off
+
+ // Run experiment
+ while( t.read() < start_period + traj_period + end_period) {
+
+ // Read encoders to get motor states
+ angle1 = encoderA.getPulses() *PULSE_TO_RAD + angle1_init;
+ velocity1 = encoderA.getVelocity() * PULSE_TO_RAD;
+
+ angle2 = encoderB.getPulses() * PULSE_TO_RAD + angle2_init;
+ velocity2 = encoderB.getVelocity() * PULSE_TO_RAD;
+
+ const float th1 = angle1;
+ const float th2 = angle2;
+ const float dth1= velocity1;
+ const float dth2= velocity2;
+
+ // Calculate the Jacobian
+ float Jx_th1 = l_AC*cos(th1+th2)+l_DE*cos(th1)+l_OB*cos(th1);
+ float Jx_th2 = l_AC*cos(th1+th2);
+ float Jy_th1 = l_AC*sin(th1+th2)+l_DE*sin(th1)+l_OB*sin(th1);
+ float Jy_th2 = l_AC*sin(th1+th2);
+
+
+ // Calculate the forward kinematics (position and velocity)
+ float xFoot = l_AC*sin(th1+th2)+l_DE*sin(th1)+l_OB*sin(th1);
+ float yFoot = -l_AC*cos(th1+th2)-l_DE*cos(th1)-l_OB*cos(th1);
+ float dxFoot = Jx_th1*dth1+Jx_th2*dth2;
+ float dyFoot = Jy_th1*dth1+Jy_th2*dth2;
+
+ // Set gains based on buffer and traj times, then calculate desired x,y from Bezier trajectory at current time if necessary
+ float teff = 0;
+ float vMult = 0;
+ if( t < start_period) {
+ if (K_xx > 0 || K_yy > 0) {
+ K_xx = 1; // for joint space control, set this to 1; for Cartesian space control, set this to 50
+ K_yy = 1; // for joint space control, set this to 1; for Cartesian space control, set this to 50
+ D_xx = 0.1; // for joint space control, set this to 0.1; for Cartesian space control, set this to 2
+ D_yy = 0.1; // for joint space control, set this to 0.1; for Cartesian space control, set this to 2
+ K_xy = 0;
+ D_xy = 0;
+ }
+ teff = 0;
+ }
+ else if (t < start_period + traj_period)
+ {
+ K_xx = input_params[5]; // Foot stiffness N/m
+ K_yy = input_params[6]; // Foot stiffness N/m
+ K_xy = input_params[7]; // Foot stiffness N/m
+ D_xx = input_params[8]; // Foot damping N/(m/s)
+ D_yy = input_params[9]; // Foot damping N/(m/s)
+ D_xy = input_params[10]; // Foot damping N/(m/s)
+ teff = (t-start_period);
+ vMult = 1;
+ }
+ else
+ {
+ teff = traj_period;
+ vMult = 0;
+ }
+
+ // Get desired foot positions and velocities
+ float rDesFoot[2] , vDesFoot[2];
+ rDesFoot_bez.evaluate(teff/traj_period,rDesFoot);
+ rDesFoot_bez.evaluateDerivative(teff/traj_period,vDesFoot);
+ vDesFoot[0]/=traj_period;
+ vDesFoot[1]/=traj_period;
+ vDesFoot[0]*=vMult;
+ vDesFoot[1]*=vMult;
+
+ // Calculate the inverse kinematics (joint positions and velocities) for desired joint angles
+ float xFoot_inv = -rDesFoot[0];
+ float yFoot_inv = rDesFoot[1];
+ float l_OE = sqrt( (pow(xFoot_inv,2) + pow(yFoot_inv,2)) );
+ float alpha = abs(acos( (pow(l_OE,2) - pow(l_AC,2) - pow((l_OB+l_DE),2))/(-2.0f*l_AC*(l_OB+l_DE)) ));
+ float th2_des = -(3.14159f - alpha);
+ float th1_des = -((3.14159f/2.0f) + atan2(yFoot_inv,xFoot_inv) - abs(asin( (l_AC/l_OE)*sin(alpha) )));
+
+ float dd = (Jx_th1*Jy_th2 - Jx_th2*Jy_th1);
+ float dth1_des = (1.0f/dd) * ( Jy_th2*vDesFoot[0] - Jx_th2*vDesFoot[1] );
+ float dth2_des = (1.0f/dd) * ( -Jy_th1*vDesFoot[0] + Jx_th1*vDesFoot[1] );
+
+ // Calculate error variables
+ float e_x = 0;
+ float e_y = 0;
+ float de_x = 0;
+ float de_y = 0;
+
+ // Calculate virtual force on foot
+ float fx = K_xx*(rDesFoot[0]-xFoot) +K_xy*(rDesFoot[1]-yFoot)+D_xx*(vDesFoot[0]-dxFoot)+D_xy*(vDesFoot[1]-dyFoot);
+ float fy = K_xy*(rDesFoot[0]-xFoot) + K_yy*(rDesFoot[1]-yFoot) + D_xy*(vDesFoot[0]-xFoot)+D_yy*(vDesFoot[1]-dyFoot);
+
+ // Set desired currents
+ current_des1 = (Jx_th1*fx+Jy_th1*fy)/k_t;
+ current_des2 = (Jx_th2*fx+Jy_th2*fy)/k_t;
+ current_des3 = (Jx_th1*fx+Jy_th1*fy)/k_t;
+ current_des4 = (Jx_th2*fx+Jy_th2*fy)/k_t;
+
+
+
+ // Joint impedance
+ // sub Kxx for K1, Dxx for D1, Kyy for K2, Dyy for D2
+ // Note: Be careful with signs now that you have non-zero desired angles!
+ // Your equations should be of the form i_d = K1*(q1_d - q1) + D1*(dq1_d - dq1)
+
+ //PART 0A FIRST
+// float q1_d=0;
+// float dq1_d=0;
+// current_des1 = (K_xx*(q1_d-th1) + D_xx*(dq1_d-dth1))/k_t;
+// current_des2 = 0;
+
+// PART 2
+// float q1_d=th1_des;
+// float dq1_d=dth1_des;
+// float q2_d=th2_des;
+// float dq2_d=dth2_des;
+// current_des1 = (K_xx*(q1_d-th1) + D_xx*(dq1_d-dth1))/k_t;
+// current_des2 = (K_yy*(q2_d-th2) + D_yy*(dq2_d-dth2))/k_t;
+
+
+
+ /* PART 3!!!!!!!!!!!!!!!!*/
+
+ // Cartesian impedance
+ // Note: As with the joint space laws, be careful with signs!
+// current_des1 = 0;
+// current_des2 = 0;
+
+
+ // Form output to send to MATLAB
+ float output_data[NUM_OUTPUTS];
+ // current time
+ output_data[0] = t.read();
+ // motor 1 state
+ output_data[1] = angle1;
+ output_data[2] = velocity1;
+ output_data[3] = current1;
+ output_data[4] = current_des1;
+ output_data[5] = duty_cycle1;
+ // motor 2 state
+ output_data[6] = angle2;
+ output_data[7] = velocity2;
+ output_data[8] = current2;
+ output_data[9] = current_des2;
+ output_data[10]= duty_cycle2;
+ // foot state
+ output_data[11] = xFoot;
+ output_data[12] = yFoot;
+ output_data[13] = dxFoot;
+ output_data[14] = dyFoot;
+ output_data[15] = rDesFoot[0];
+ output_data[16] = rDesFoot[1];
+ output_data[17] = vDesFoot[0];
+ output_data[18] = vDesFoot[1];
+
+ // Send data to MATLAB
+ server.sendData(output_data,NUM_OUTPUTS);
+
+ wait_us(impedance_control_period_us);
+ }
+
+ // Cleanup after experiment
+ server.setExperimentComplete();
+ currentLoop.detach();
+ motorShield.motorAWrite(0, 0); //turn motor A off
+ motorShield.motorBWrite(0, 0); //turn motor B off
+ motorShield.motorCWrite(0,0);
+ motorShield.motorDWrite(0,0);
+
+ } // end if
+
+ } // end while
+
+} // end main
+