Cooper Liu / Mbed 2 deprecated ICRSEurobot13

Colour sensors calibrated

Dependencies:   mbed-rtos mbed Servo QEI

Fork of ICRSEurobot13 by Thomas Branch

Processes/Motion/motion.cpp@31:791739422122, 2013-04-10 (annotated)

Committer:
rsavitski
Date:
Wed Apr 10 18:03:32 2013 +0000
Revision:
31:791739422122
Parent:
26:b16f1045108f
Child:
33:e3f633620816
ai layer thread

Who changed what in which revision?

UserRevisionLine numberNew contents of line
rsavitski 25:50805ef8c499 1 ////////////////////////////////////////////////////////////////////////////////
rsavitski 25:50805ef8c499 2 // Motion control unit
rsavitski 25:50805ef8c499 3 ////////////////////////////////////////////////////////////////////////////////
rsavitski 25:50805ef8c499 4 // Takes current state of the robot and target waypoint,
rsavitski 25:50805ef8c499 5 // calculates desired forward and angular velocities and requests those from the motor control layer.
rsavitski 25:50805ef8c499 6 ////////////////////////////////////////////////////////////////////////////////
rsavitski 25:50805ef8c499 7
rsavitski 25:50805ef8c499 8 #include "motion.h"
rsavitski 25:50805ef8c499 9
rsavitski 25:50805ef8c499 10 namespace motion
rsavitski 25:50805ef8c499 11 {
rsavitski 25:50805ef8c499 12
rsavitski 25:50805ef8c499 13 void motionlayer(void const *dummy)
rsavitski 31:791739422122 14 {
rsavitski 25:50805ef8c499 15 // get target waypoint from AI
rsavitski 25:50805ef8c499 16 Waypoint target_waypoint = *AI::current_waypoint;
rsavitski 25:50805ef8c499 17
rsavitski 25:50805ef8c499 18 // get current state from Kalman
rsavitski 25:50805ef8c499 19 State current_state = Kalman::getState();
rsavitski 25:50805ef8c499 20
rsavitski 25:50805ef8c499 21 float delta_x = target_waypoint.x - current_state.x;
rsavitski 25:50805ef8c499 22 float delta_y = target_waypoint.y - current_state.y;
rsavitski 25:50805ef8c499 23
madcowswe 26:b16f1045108f 24 //printf("motion sees deltax: %f deltay %f\r\n", delta_x, delta_y);
rsavitski 25:50805ef8c499 25
madcowswe 26:b16f1045108f 26 float distance_err = hypot(delta_x, delta_y);
madcowswe 26:b16f1045108f 27
madcowswe 26:b16f1045108f 28 float angle_err = constrainAngle(atan2(delta_y, delta_x) - current_state.theta);
rsavitski 25:50805ef8c499 29
rsavitski 31:791739422122 30 // is the waypoint reached
rsavitski 31:791739422122 31 if (distance_err < target_waypoint.pos_threshold)
rsavitski 31:791739422122 32 {
rsavitski 31:791739422122 33 distance_err = 0;
rsavitski 31:791739422122 34 }
rsavitski 31:791739422122 35 if (abs(angle_err) < target_waypoint.angle_threshold)
rsavitski 31:791739422122 36 {
rsavitski 31:791739422122 37 angle_err = 0;
rsavitski 31:791739422122 38 }
rsavitski 31:791739422122 39
rsavitski 31:791739422122 40 AI::waypoint_flag_mutex.lock(); // proper way would be to construct a function to evaluate the condition and pass the function pointer to a conditional setter function for reached flag
rsavitski 31:791739422122 41 if (distance_err == 0 && angle_err == 0)
rsavitski 31:791739422122 42 {
rsavitski 31:791739422122 43 AI::setWaypointReached();
rsavitski 31:791739422122 44 return;
rsavitski 31:791739422122 45 }
rsavitski 31:791739422122 46 AI::waypoint_flag_mutex.unlock();
rsavitski 25:50805ef8c499 47
rsavitski 25:50805ef8c499 48 // angular velocity controller
madcowswe 26:b16f1045108f 49 const float p_gain_av = 0.3; //TODO: tune
rsavitski 25:50805ef8c499 50
madcowswe 26:b16f1045108f 51 const float max_av = 0.2*PI; // radians per sec //TODO: tune
rsavitski 25:50805ef8c499 52
rsavitski 25:50805ef8c499 53 // angle error [-pi, pi]
rsavitski 25:50805ef8c499 54 float angular_v = p_gain_av * angle_err;
rsavitski 25:50805ef8c499 55
rsavitski 25:50805ef8c499 56 // constrain range
rsavitski 25:50805ef8c499 57 if (angular_v > max_av)
rsavitski 25:50805ef8c499 58 angular_v = max_av;
rsavitski 25:50805ef8c499 59 else if (angular_v < -max_av)
rsavitski 25:50805ef8c499 60 angular_v = -max_av;
rsavitski 25:50805ef8c499 61
rsavitski 25:50805ef8c499 62
rsavitski 25:50805ef8c499 63 // forward velocity controller
madcowswe 26:b16f1045108f 64 const float p_gain_fv = 0.3; //TODO: tune
rsavitski 25:50805ef8c499 65
madcowswe 26:b16f1045108f 66 float max_fv = 0.2; // meters per sec //TODO: tune
rsavitski 25:50805ef8c499 67 const float angle_envelope_exponent = 8.0; //TODO: tune
rsavitski 25:50805ef8c499 68
rsavitski 25:50805ef8c499 69 // control, distance_err in meters
rsavitski 25:50805ef8c499 70 float forward_v = p_gain_fv * distance_err;
rsavitski 25:50805ef8c499 71
rsavitski 25:50805ef8c499 72 // control the forward velocity envelope based on angular error
rsavitski 25:50805ef8c499 73 max_fv = max_fv * pow(cos(angle_err/2), angle_envelope_exponent);
rsavitski 25:50805ef8c499 74
rsavitski 25:50805ef8c499 75 // constrain range
rsavitski 25:50805ef8c499 76 if (forward_v > max_fv)
rsavitski 25:50805ef8c499 77 forward_v = max_fv;
rsavitski 25:50805ef8c499 78 else if (forward_v < -max_fv)
rsavitski 25:50805ef8c499 79 forward_v = -max_fv;
madcowswe 26:b16f1045108f 80
madcowswe 26:b16f1045108f 81 //printf("fwd: %f, omega: %f\r\n", forward_v, angular_v);
rsavitski 25:50805ef8c499 82
rsavitski 31:791739422122 83 // pass values to the motor control
rsavitski 25:50805ef8c499 84 MotorControl::set_fwdcmd(forward_v);
madcowswe 26:b16f1045108f 85 MotorControl::set_omegacmd(angular_v);
rsavitski 25:50805ef8c499 86 }
rsavitski 25:50805ef8c499 87
rsavitski 25:50805ef8c499 88 } //namespace