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"""Subscribe /feedback/joint_states and preview camera."""
import math
import cv2
import rclpy
from rclpy.node import Node
from sensor_msgs.msg import JointState
FEEDBACK_TOPIC = "/feedback/joint_states"
CONTROL_TOPIC = "/control/joint_states"
CAMERA_INDEX = 4
TARGET_NAMES = ["joint1", "joint2", "joint3", "joint4", "joint5", "joint6", "gripper"]
GRIPPER_MIN_M = 0.0
GRIPPER_MAX_M = 0.1
JOINT2_DELTA_RAD = 0.12
JOINT3_DELTA_RAD = 0.12
JOINT4_DELTA_RAD = 0.06
GRIPPER_DELTA_M = 0.05
class JointStatePrinter(Node):
def __init__(self) -> None:
super().__init__("joint_state_printer")
self.latest_msg: JointState | None = None
self.latest_frame_shape: tuple[int, int, int] | None = None
self.show_window = False
self.window_name = "camera_preview"
self.cap = cv2.VideoCapture(CAMERA_INDEX, cv2.CAP_V4L2)
if self.cap.isOpened():
self.get_logger().info(f"OpenCV camera opened: /dev/video{CAMERA_INDEX}")
try:
cv2.namedWindow(self.window_name, cv2.WINDOW_NORMAL)
cv2.resizeWindow(self.window_name, 1280, 720)
self.show_window = True
except cv2.error:
self.get_logger().warn("No GUI backend, run without preview window.")
else:
self.get_logger().warn(f"OpenCV camera open failed: /dev/video{CAMERA_INDEX}")
self.ctrl_pub = self.create_publisher(JointState, CONTROL_TOPIC, 10)
self.traj_msgs: list[JointState] = []
self.traj_idx = 0
self.traj_cycle = 0
self.traj_started = False
self.create_subscription(JointState, FEEDBACK_TOPIC, self._callback, 10)
self.create_timer(0.05, self._read_camera_frame)
self.create_timer(0.05, self._publish_traj_step)
self.create_timer(1.0, self._print_latest)
self.get_logger().info(
f"Subscribed to {FEEDBACK_TOPIC}; publish planned stream to {CONTROL_TOPIC} at 20Hz"
)
def _callback(self, msg: JointState) -> None:
self.latest_msg = msg
if self.traj_started:
return
base = self._extract_target_positions(msg)
if base is None:
self.get_logger().warn("Feedback JointState missing required joints, waiting next message.")
return
self.traj_msgs = self._build_trajectory(base, steps=50)
self.traj_idx = 0
self.traj_cycle = 0
self.traj_started = True
self.get_logger().info("Generated 50-step motion stream from current feedback position (loop mode).")
def _extract_target_positions(self, msg: JointState) -> list[float] | None:
name_to_pos = {n: p for n, p in zip(msg.name, msg.position)}
out: list[float] = []
for joint in TARGET_NAMES[:6]:
if joint not in name_to_pos:
return None
out.append(float(name_to_pos[joint]))
if "gripper" in name_to_pos:
out.append(float(name_to_pos["gripper"]))
elif "gripper_joint1" in name_to_pos and "gripper_joint2" in name_to_pos:
out.append(abs(float(name_to_pos["gripper_joint1"])) + abs(float(name_to_pos["gripper_joint2"])))
else:
out.append(0.05)
out[6] = max(GRIPPER_MIN_M, min(GRIPPER_MAX_M, out[6]))
return out
def _build_trajectory(self, base: list[float], steps: int) -> list[JointState]:
traj: list[JointState] = []
for i in range(steps):
t = i / max(steps - 1, 1)
s = math.sin(2.0 * math.pi * t)
s2 = math.sin(4.0 * math.pi * t)
p = list(base)
p[1] += JOINT2_DELTA_RAD * s
p[2] += -JOINT3_DELTA_RAD * s
p[3] += JOINT4_DELTA_RAD * s2
p[6] = max(GRIPPER_MIN_M, min(GRIPPER_MAX_M, p[6] + GRIPPER_DELTA_M * s))
m = JointState()
m.name = TARGET_NAMES
m.position = p
m.velocity = []
m.effort = [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.5]
traj.append(m)
return traj
def _publish_traj_step(self) -> None:
if not self.traj_started or not self.traj_msgs:
return
if self.traj_idx >= len(self.traj_msgs):
self.traj_idx = 0
self.traj_cycle += 1
self.get_logger().info(f"Looping motion stream, cycle={self.traj_cycle}")
msg = self.traj_msgs[self.traj_idx]
msg.header.stamp = self.get_clock().now().to_msg()
self.ctrl_pub.publish(msg)
self.traj_idx += 1
def _read_camera_frame(self) -> None:
if not self.cap.isOpened():
return
ok, frame = self.cap.read()
if not ok:
return
self.latest_frame_shape = frame.shape
if self.show_window:
cv2.imshow(self.window_name, frame)
key = cv2.waitKey(1) & 0xFF
if key == ord("q"):
self.get_logger().info("Pressed q, shutting down...")
if rclpy.ok():
rclpy.shutdown()
def _print_latest(self) -> None:
if self.latest_msg is None:
return
msg = self.latest_msg
stamp = f"{msg.header.stamp.sec}.{msg.header.stamp.nanosec:09d}"
print("==== /feedback/joint_states ====")
print(f"stamp: {stamp}")
print(f"name: {list(msg.name)}")
print(f"position: {list(msg.position)}")
print(f"velocity: {list(msg.velocity)}")
print(f"effort: {list(msg.effort)}")
if self.traj_started:
print(f"stream_progress: {self.traj_idx}/{len(self.traj_msgs)} cycle={self.traj_cycle}")
if self.latest_frame_shape is not None:
h, w, c = self.latest_frame_shape
print(f"camera_frame: {w}x{h} channels={c}")
else:
print("camera_frame: N/A")
def main() -> None:
rclpy.init()
node = JointStatePrinter()
try:
rclpy.spin(node)
except KeyboardInterrupt:
pass
finally:
if node.cap.isOpened():
node.cap.release()
if node.show_window:
cv2.destroyAllWindows()
node.destroy_node()
if rclpy.ok():
rclpy.shutdown()
if __name__ == "__main__":
main()
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