我不确定我是否正确理解了您的问题，但似乎您没有考虑机器人的方向（theta）时，将激光扫描测量值放入占用网格。在将激光扫描插入Map之前，应根据机器人的方向旋转激光扫描。下面是应用了旋转的函数的更新版本：

import math

def mapping(x_pos_t , y_pos_t, theta, scan_msg, map_msg):
    # convert laser scans to occupancy grid
    for i, dist in enumerate(scan_msg.ranges):
        if dist < scan_msg.range_max:
            # Calculate the angle of the current laser scan measurement
            angle = scan_msg.angle_min + i * scan_msg.angle_increment + theta
            
            # Rotate the laser scan measurements by the robot's orientation (theta)
            x = int((x_pos_t + dist * math.cos(angle)) / map_msg.info.resolution)
            y = int((y_pos_t + dist * math.sin(angle)) / map_msg.info.resolution)

            if x >= 0 and x < map_msg.info.width and y >= 0 and y < map_msg.info.height:
                map_msg.data[y * map_msg.info.width + x] = 100

    return map_msg

这应当有助于在机器人旋转时将激光扫描测量与占用网格对准。