mirror of https://github.com/ArduPilot/ardupilot
126 lines
3.6 KiB
C++
126 lines
3.6 KiB
C++
/*
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/*
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simple Gripper (OpenGrab EPM) simulation class
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*/
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#include "SIM_Gripper_EPM.h"
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#include "AP_HAL/AP_HAL.h"
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#include <stdio.h>
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#include <AP_Math/AP_Math.h>
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extern const AP_HAL::HAL& hal;
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using namespace SITL;
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// table of user settable parameters
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const AP_Param::GroupInfo Gripper_EPM::var_info[] = {
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// @Param: ENABLE
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// @DisplayName: Gripper servo Sim enable/disable
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// @Description: Allows you to enable (1) or disable (0) the gripper servo simulation
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// @Values: 0:Disabled,1:Enabled
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// @User: Advanced
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AP_GROUPINFO("ENABLE", 0, Gripper_EPM, gripper_emp_enable, 0),
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// @Param: PIN
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// @DisplayName: Gripper emp pin
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// @Description: The pin number that the gripper emp is connected to. (start at 1)
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// @Range: 0 15
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// @User: Advanced
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AP_GROUPINFO("PIN", 1, Gripper_EPM, gripper_emp_servo_pin, -1),
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AP_GROUPEND
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};
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/*
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update gripper state
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*/
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void Gripper_EPM::update_servobased(int16_t gripper_pwm)
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{
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if (!servo_based) {
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return;
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}
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if (gripper_pwm >= 0) {
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demand = (gripper_pwm - 1000) * 0.001f; // 0.0 - 1.0
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if (is_negative(demand)) { // never updated
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demand = 0.0f;
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}
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}
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}
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void Gripper_EPM::update_from_demand()
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{
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const uint64_t now = AP_HAL::micros64();
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const float dt = (now - last_update_us) * 1.0e-6f;
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// decay the field
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field_strength = field_strength * (100.0f - field_decay_rate * dt) / 100.0f;
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// note that "demand" here is just an on/off switch; we only care
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// about which range it falls into
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if (demand > 0.6f) {
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// we are instructed to grip harder
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field_strength = field_strength + (100.0f - field_strength) * field_strength_slew_rate / 100.0f * dt;
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} else if (demand < 0.4f) {
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// we are instructed to loosen grip
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field_strength = field_strength * (100.0f - field_degauss_rate * dt) / 100.0f;
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} else {
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// neutral; no demanded change
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}
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if (should_report()) {
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hal.console->printf("demand=%f\n", demand);
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hal.console->printf("Field strength: %f%%\n", field_strength);
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hal.console->printf("Field strength: %f Tesla\n", tesla());
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last_report_us = now;
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reported_field_strength = field_strength;
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}
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last_update_us = now;
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}
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void Gripper_EPM::update(const struct sitl_input &input)
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{
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const int16_t gripper_pwm = gripper_emp_servo_pin >= 1 ? input.servos[gripper_emp_servo_pin-1] : -1;
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update_servobased(gripper_pwm);
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update_from_demand();
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}
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bool Gripper_EPM::should_report() const
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{
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if (AP_HAL::micros64() - last_report_us < report_interval) {
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return false;
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}
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if (fabsf(reported_field_strength - field_strength) > 10.0) {
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return true;
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}
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return false;
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}
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float Gripper_EPM::tesla() const
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{
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// https://en.wikipedia.org/wiki/Orders_of_magnitude_(magnetic_field)
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// 200N lifting capacity ~= 2.5T
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const float percentage_to_tesla = 0.25f;
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return static_cast<float>(percentage_to_tesla * field_strength / 100.0f);
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}
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