forked from ZhengLiu-cart/IK_qp
try mujoco
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LiuzhengSJ
250
kine_ctrl/rm75_mujoco.py
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250
kine_ctrl/rm75_mujoco.py
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#!/usr/bin/env python3
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"""
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RM75 Robot Controller for URDF without actuators
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Direct joint position control (kinematic mode)
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"""
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import mujoco
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import mujoco.viewer
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import numpy as np
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import time
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from pathlib import Path
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class RM75Controller:
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def __init__(self, urdf_path: str ="/home/zl/Downloads/urdf_rm75/RM75-B.urdf", enable_viewer: bool = True):
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"""
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Initialize RM75 robot simulation from URDF
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Args:
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urdf_path: Path to RM75-B.urdf file
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enable_viewer: Show visualization window
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"""
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# Load model
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self.model = mujoco.MjModel.from_xml_path(urdf_path)
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self.data = mujoco.MjData(self.model)
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# Robot info
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self.n_joints = self.model.njnt
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self.n_actuators = self.model.nu
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print(f"✓ Loaded RM75 robot")
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print(f" - Joints: {self.n_joints}")
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print(f" - Actuators: {self.n_actuators} (using direct joint control)")
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print(f" - Bodies: {self.model.nbody}")
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# Get joint names for reference
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self.joint_names = []
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for i in range(self.n_joints):
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self.joint_names.append(self.model.joint(i).name)
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print(f" - Joints: {', '.join(self.joint_names)}")
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# Store home position (current joint angles)
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self.home_position = self.data.qpos[:self.n_joints].copy()
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print(f" - Home position: {self.home_position}")
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# For position control without actuators, we'll use qpos directly
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self.use_actuators = self.n_actuators > 0
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# Viewer
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self.viewer = None
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if enable_viewer:
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try:
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self.viewer = mujoco.viewer.launch_passive(self.model, self.data)
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print("✓ Viewer launched successfully")
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except Exception as e:
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print(f"Warning: Could not launch viewer: {e}")
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self.viewer = None
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def get_joint_positions(self):
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"""Get current joint angles (radians)"""
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return self.data.qpos[:self.n_joints].copy()
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def get_joint_velocities(self):
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"""Get current joint velocities (rad/s)"""
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return self.data.qvel[:self.n_joints].copy()
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def get_end_effector_pose(self):
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"""Get end-effector position and orientation"""
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# Last body is usually end-effector
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end_effector_id = self.model.nbody - 1
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position = self.data.xpos[end_effector_id].copy()
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orientation = self.data.xmat[end_effector_id].copy().reshape(3, 3)
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return position, orientation
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def set_joint_positions(self, positions):
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"""
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Set joint positions directly (kinematic control)
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Args:
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positions: Target joint angles in radians (length should match n_joints)
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"""
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if len(positions) != self.n_joints:
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print(f"Warning: Expected {self.n_joints} joints, got {len(positions)}")
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positions = positions[:self.n_joints]
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# Directly set joint positions (kinematic control)
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self.data.qpos[:self.n_joints] = positions
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# Also set velocities to zero to avoid unwanted motion
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self.data.qvel[:self.n_joints] = 0
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def step(self):
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"""Advance simulation one step"""
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mujoco.mj_step(self.model, self.data)
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if self.viewer:
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self.viewer.sync()
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def step_n(self, n_steps: int):
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"""Advance simulation by N steps"""
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for _ in range(n_steps):
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self.step()
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def move_to_position(self, target_positions, steps=500):
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"""
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Smoothly move to target joint positions
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Args:
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target_positions: Target joint angles
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steps: Number of simulation steps for the movement
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"""
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current = self.get_joint_positions()
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target = np.array(target_positions[:self.n_joints])
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for i in range(steps):
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# Linear interpolation
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alpha = (i + 1) / steps
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positions = current + alpha * (target - current)
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self.set_joint_positions(positions)
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self.step()
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# Ensure exact target
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self.set_joint_positions(target)
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self.step_n(10)
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def run_trajectory(self, trajectory_points, steps_between_points=500):
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"""
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Execute a joint trajectory
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Args:
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trajectory_points: List of joint position arrays
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steps_between_points: Steps between each point
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"""
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print(f"Executing trajectory with {len(trajectory_points)} points...")
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for i, target in enumerate(trajectory_points):
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print(f" Moving to point {i + 1}/{len(trajectory_points)}")
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self.move_to_position(target, steps_between_points)
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print("✓ Trajectory complete")
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def run_forever(self, dt=0.01):
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"""Run simulation with real-time control loop"""
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print("\n✓ Simulation running. Close viewer window to exit.\n")
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try:
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while self.viewer and self.viewer.is_running():
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self.step()
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time.sleep(dt)
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except KeyboardInterrupt:
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print("\n✓ Stopped by user")
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finally:
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if self.viewer:
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self.viewer.close()
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def print_state(self):
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"""Print current robot state"""
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positions = self.get_joint_positions()
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print(f"Joint positions (rad): {[f'{p:.3f}' for p in positions]}")
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# Test trajectories for RM75
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def create_sine_wave_trajectory(controller, duration_seconds=5, frequency=0.5):
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"""Create a sine wave trajectory for testing"""
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steps = int(duration_seconds / controller.model.opt.timestep)
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trajectory = []
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for i in range(steps):
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t = i * controller.model.opt.timestep
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positions = controller.home_position.copy()
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# Create sine wave motion on first 3 joints (shoulder, elbow, wrist)
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positions[0] = controller.home_position[0] + 0.5 * np.sin(2 * np.pi * frequency * t)
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positions[1] = controller.home_position[1] + 0.3 * np.sin(2 * np.pi * frequency * t + 1.0)
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positions[2] = controller.home_position[2] + 0.2 * np.sin(2 * np.pi * frequency * t + 2.0)
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trajectory.append(positions)
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return trajectory
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if __name__ == "__main__":
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# Path to your URDF
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urdf_file = "/home/zl/Downloads/urdf_rm75/RM75-B.urdf"
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# Check if file exists
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if not Path(urdf_file).exists():
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print(f"Error: URDF file not found at {urdf_file}")
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exit(1)
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# Create robot controller
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print("Initializing RM75 Controller...")
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robot = RM75Controller(urdf_file, enable_viewer=True)
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if robot.viewer is None:
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print("Error: Could not initialize viewer. Running without visualization.")
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# Give time for viewer to initialize
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time.sleep(1)
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# Test 1: Print current state
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print("\n>>> Current robot state:")
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robot.print_state()
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# Test 2: Move to home position
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print("\n>>> Moving to home position...")
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robot.move_to_position(robot.home_position, steps=300)
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robot.print_state()
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# Test 3: Create and execute a pose sequence
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print("\n>>> Testing different poses...")
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# Pose 1: Slightly raised arm
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pose1 = robot.home_position.copy()
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pose1[0] = 0.5 # Joint 1
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pose1[1] = -0.3 # Joint 2
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pose1[2] = 0.2 # Joint 3
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# Pose 2: Extended arm
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pose2 = robot.home_position.copy()
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pose2[0] = 0.8
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pose2[1] = -0.5
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pose2[2] = 0.4
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pose2[3] = 0.3 # Joint 4
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# Pose 3: Folded position
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pose3 = robot.home_position.copy()
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pose3[0] = -0.5
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pose3[1] = 0.3
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pose3[2] = -0.2
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trajectory = [pose1, pose2, pose3, robot.home_position]
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robot.run_trajectory(trajectory, steps_between_points=400)
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# Test 4: Continuous sine wave motion (5 seconds)
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print("\n>>> Starting sine wave motion (5 seconds)...")
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sine_trajectory = create_sine_wave_trajectory(robot, duration_seconds=5, frequency=0.8)
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robot.run_trajectory(sine_trajectory, steps_between_points=1)
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# Return to home
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print("\n>>> Returning to home position...")
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robot.move_to_position(robot.home_position, steps=300)
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print("\n✓ Demo complete!")
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# Keep viewer open until user closes
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if robot.viewer:
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print("\nPress Ctrl+C in terminal to exit, or close the viewer window.")
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robot.run_forever()
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else:
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print("\nSimulation completed.")
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