bldc/applications/app_balance.c

/*
	Copyright 2019 Mitch Lustig

	This file is part of the VESC firmware.

	The VESC firmware is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    The VESC firmware is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
    */

#include "conf_general.h"

#include "ch.h" // ChibiOS
#include "hal.h" // ChibiOS HAL
#include "mc_interface.h" // Motor control functions
#include "hw.h" // Pin mapping on this hardware
#include "timeout.h" // To reset the timeout
#include "commands.h"
#include "imu/imu.h"
#include "imu/ahrs.h"
#include "utils.h"
#include "datatypes.h"


#include <math.h>

// Data type
typedef enum {
	STARTUP = 0,
	RUNNING,
	FAULT,
	DEAD
} BalanceState;

typedef enum {
	CENTERING = 0,
	TILTBACK
} SetpointAdjustmentType;

// Balance thread
static THD_FUNCTION(balance_thread, arg);
static THD_WORKING_AREA(balance_thread_wa, 2048); // 2kb stack for this thread

static volatile balance_config balance_conf;
static thread_t *app_thread;

// Values used in loop
static BalanceState state;
static float m_angle, c_angle;
static float proportional, integral, derivative;
static float last_proportional;
static float pid_value;
static float setpoint, setpoint_target;
static SetpointAdjustmentType setpointAdjustmentType;
static float startup_step_size, tiltback_step_size;
static systime_t current_time, last_time, diff_time;
static systime_t startup_start_time, startup_diff_time;

// Values read to pass in app data to GUI
static float motor_current;
static float motor_position;

void app_balance_configure(balance_config *conf) {
	balance_conf = *conf;
}

void app_balance_start(void) {

	// Reset all Values
	state = STARTUP;
	m_angle = 0;
	c_angle = 0;
	proportional = 0;
	integral = 0;
	derivative = 0;
	last_proportional = 0;
	pid_value = 0;
	setpoint = 0;
	setpoint_target = 0;
	setpointAdjustmentType = CENTERING;
	startup_step_size = 0;
	tiltback_step_size = 0;
	current_time = 0;
	last_time = 0;
	diff_time = 0;
	startup_start_time = 0;
	startup_diff_time = 0;

	// Start the balance thread
	app_thread = chThdCreateStatic(balance_thread_wa, sizeof(balance_thread_wa), NORMALPRIO, balance_thread, NULL);
}

void app_balance_stop(void) {
	if(app_thread != NULL){
		chThdTerminate(app_thread);
		chThdWait(app_thread);
	}
	mc_interface_set_current(0);
}

float app_balance_get_pid_output(void) {
	return pid_value;
}
float app_balance_get_m_angle(void) {
	return m_angle;
}
float app_balance_get_c_angle(void) {
	return c_angle;
}
uint32_t app_balance_get_diff_time(void) {
	return ST2US(diff_time);
}
float app_balance_get_motor_current(void) {
	return motor_current;
}
float app_balance_get_motor_position(void) {
	return motor_position;
}
uint16_t app_balance_get_state(void) {
	return state;
}

float get_setpoint_adjustment_step_size(void){
	switch(setpointAdjustmentType){
		case (CENTERING):
			return startup_step_size;
		case (TILTBACK):
			return tiltback_step_size;
	}
	return 0;
}

float apply_deadzone(float error){
	if(balance_conf.deadzone == 0){
		return error;
	}

	if(error < balance_conf.deadzone && error > -balance_conf.deadzone){
		return 0;
	} else if(error > balance_conf.deadzone){
		return error - balance_conf.deadzone;
	} else {
		return error + balance_conf.deadzone;
	}
}

static THD_FUNCTION(balance_thread, arg) {
	(void)arg;
	chRegSetThreadName("APP_BALANCE");

	// Do one off config
	startup_step_size = balance_conf.startup_speed / balance_conf.hertz;
	tiltback_step_size = balance_conf.tiltback_speed / balance_conf.hertz;

	state = STARTUP;
	setpointAdjustmentType = CENTERING;

	while (!chThdShouldTerminateX()) {
		// Update times
		current_time = chVTGetSystemTimeX();
		if(last_time == 0){
		  last_time = current_time;
		}
		diff_time = current_time - last_time;
		last_time = current_time;

		// Read values for GUI
		motor_current = mc_interface_get_tot_current_directional_filtered();
		motor_position = mc_interface_get_pid_pos_now();

		// Get the values we want
		switch(balance_conf.m_axis){
			case (PITCH):
				m_angle = imu_get_pitch() * 180.0f / M_PI;;
				break;
			case (ROLL):
				m_angle = imu_get_roll() * 180.0f / M_PI;
				break;
			case (YAW):
				m_angle = imu_get_yaw() * 180.0f / M_PI;
				break;
		}
		switch(balance_conf.c_axis){
			case (PITCH):
				c_angle = imu_get_pitch() * 180.0f / M_PI;;
				break;
			case (ROLL):
				c_angle = imu_get_roll() * 180.0f / M_PI;
				break;
			case (YAW):
				c_angle = imu_get_yaw() * 180.0f / M_PI;
				break;
		}

		// State based logic
		switch(state){
			case (STARTUP):
				if(startup_start_time == 0){
					startup_start_time = current_time;
				}
				startup_diff_time = current_time - startup_start_time;

				// Calibration is done
				if(ST2MS(startup_diff_time) > 1000){
					// Set fault and wait for valid startup condition
					state = FAULT;
					startup_start_time = 0;
					startup_diff_time = 0;
				}
				break;
			case (RUNNING):
				// Check for overspeed
				if(fabsf(mc_interface_get_duty_cycle_now()) > balance_conf.overspeed_duty){
					state = DEAD;
				}

				// Check for fault
				if(fabsf(m_angle) > balance_conf.m_fault || fabsf(c_angle) > balance_conf.c_fault){
					state = FAULT;
				}

				// Over speed tilt back safety
				if(mc_interface_get_duty_cycle_now() > balance_conf.tiltback_duty){
					setpoint_target = balance_conf.tiltback_angle;
					setpointAdjustmentType = TILTBACK;
				} else if(mc_interface_get_duty_cycle_now() < -balance_conf.tiltback_duty){
					setpoint_target = -balance_conf.tiltback_angle;
					setpointAdjustmentType = TILTBACK;
				}else{
					setpoint_target = 0;
				}

				// Adjust setpoint
				if(setpoint != setpoint_target){
					// If we are less than one step size away, go all the way
					if(fabsf(setpoint_target - setpoint) < get_setpoint_adjustment_step_size()){
						setpoint = setpoint_target;
					}else if (setpoint_target - setpoint > 0){
						setpoint += get_setpoint_adjustment_step_size();
					}else{
						setpoint -= get_setpoint_adjustment_step_size();
					}
				}

				// Do PID maths
				proportional = setpoint - m_angle;
				// Apply deadzone
				proportional = apply_deadzone(proportional);
				// Resume real PID maths
				integral = integral + proportional;
				derivative = proportional - last_proportional;

				pid_value = (balance_conf.kp * proportional) + (balance_conf.ki * integral) + (balance_conf.kd * derivative);

				last_proportional = proportional;

				// Apply current boost
				if(pid_value > 0){
					pid_value += balance_conf.current_boost;
				}else if(pid_value < 0){
					pid_value -= balance_conf.current_boost;
				}

				// Reset the timeout
				timeout_reset();

				// Output to motor
				if(pid_value == 0){
					mc_interface_release_motor();
				}else {
					mc_interface_set_current(pid_value);
				}
				break;
			case (FAULT):
				// Check for valid startup position
				if(fabsf(m_angle) < balance_conf.startup_m_tolerance && fabsf(c_angle) < balance_conf.startup_c_tolerance){
					setpoint = m_angle;
					setpoint_target = 0;
					setpointAdjustmentType = CENTERING;
					state = RUNNING;
					break;
				}

				// Disable output
				mc_interface_set_current(0);
				break;
			case (DEAD):
				// Disable output
				mc_interface_set_current(0);
				break;
		}

		// Delay between loops
		chThdSleepMicroseconds((int)((1000.0 / balance_conf.hertz) * 1000.0));
	}

	// Disable output
	mc_interface_set_current(0);
}