完整的代码我会放到文章末尾
我们的代码分为三个部分:
1,键盘事件监控
2,速度反馈
3,主函数(主要实现控制)
首先我们创建了两个字典,一个用于改变机器人运动方向,一个用于机器人速度控制
MoveBindings = {
'w':(1, 0),
's':(-1, 0),
'a':(0, 1),
'd':(0, -1),
'q':(1, 1),
'e':(1, -1),
'z':(-1, 1),
'c':(-1, 1)
}
SpeedBindings = {
'+':(1.1, 1.1),
'-':(0.9, 0.9),
'1':(1.1, 1),
'2':(0.9, 1),
'3':(1, 1.1),
'4':(1, 0.9)
}
然后我们来看第一部分,监听键盘事件
这里我们使用了select模块,termios模块和tty模块
select模块主要用于socket通信,见识文件描述的变化,完成非阻塞方式工作
termios模块为tty提供了一个IO控制的POSIX调用的接口
tty模块主要用于更改文件描述符fd的模式
首先我们要把输入文件描述符模式改为raw,然后直接调用操作系的IO接口,监控所有带fileno()方法的文件句柄
在这里,我们只需要读取一个字节的输入流
最后我们从属性设置文件描述符fd的tty属性,返回键值
def GetKey():
tty.setraw(sys.stdin.fileno())
rlist= select.select([sys.stdin], [], [], 0.1)
if rlist:
key = sys.stdin.read(1)
else:
key = ''
termios.tcsetattr(sys.stdin, termios.TCSADRAIN, settings)
return key
第二部分我们写了一个返回速度和旋转量的函数,非常简单
def vels(speed, turn):
return "currently:\t speed %s\t turn %s" % (speed, turn)
最后是我们的主要的控制和逻辑函数
首先我们需要得带文件描述符fd的tty属性
其次就是发布速度
在后面就是对速度的一些控制代码
if __name__ == '__main__':
settings = termios.tcgetattr(sys.stdin)
rospy.init_node('teleop')
pub = rospy.Publisher('/cmd_vel', Twist, queue_size = 10)
x = 0
th = 0
status = 0
count = 0
acc = 0.1
target_speed = 0
target_turn = 0
control_speed = 0
control_turn = 0
try:
print msg
print vels(speed, turn)
while(1):
key = GetKey()
if (key in MoveBindings.keys()):
x = MoveBindings[key][0]
th = MoveBindings[key][1]
rospy.loginfo("speed is : %s \t turn is : %s " %(speed, turn))
count = 0
elif (key in SpeedBindings.keys()):
speed = speed*SpeedBindings[key][0]
turn = turn*SpeedBindings[key][1]
count = 0
print vels(speed, turn)
status = (status+1)%15
elif (key == ' ' or key == 'x'):
x = 0
th = 0
control_speed = 0
control_turn = 0
rospy.loginfo("pause the robot...")
else:
count += 1
if count > 4:
x = 0
th = 0
if key == '\x03':
break
target_speed = speed*x
target_turn = turn*th
if target_speed > control_speed:
control_speed = min(target_speed, control_speed+0.02)
elif target_speed < control_speed:
control_speed = max(target_speed, control_speed-0.02)
else:
control_speed = target_speed
if target_turn > control_turn:
control_turn = min(target_turn, control_turn+0.1)
elif target_turn < control_turn:
control_turn = max(target_turn, control_turn-0.1)
else:
control_turn = target_turn
twist = Twist()
twist.linear.x = control_speed
twist.linear.y = 0
twist.linear.z = 0
twist.angular.x = 0
twist.angular.y = 0
twist.angular.z = control_turn
pub.publish(twist)
except:
rospy.logerr("some code error, please check!!!")
finally:
twist = Twist()
twist.linear.x = 0
twist.linear.y = 0
twist.linear.z = 0
twist.angular.x = 0
twist.angular.y = 0
twist.angular.z = 0
pub.publish(twist)
termios.tcsetattr(sys.stdin, termios.TCSADRAIN, settings)
现在就是整个代码
#!/usr/bin/env python
# -*- coding: utf-8 -*-
import rospy
from geometry_msgs.msg import Twist
import sys, select, termios, tty
msg = """
Control mrobot!
---------------------------
Moving around:
u i o
j k l
m , .
q/z : increase/decrease max speeds by 10%
w/x : increase/decrease only linear speed by 10%
e/c : increase/decrease only angular speed by 10%
space key, k : force stop
anything else : stop smoothly
CTRL-C to quit
"""
moveBindings = {
'w':(1,0),
'e':(1,-1),
'a':(0,1),
'd':(0,-1),
'q':(1,1),
's':(-1,0),
'x':(-1,1),
'z':(-1,-1),
}
speedBindings={
'+':(1.1,1.1),
'-':(.9,.9),
'3':(1.1,1),
'4':(.9,1),
'5':(1,1.1),
'6':(1,.9),
}
def getKey():
# tty.setraw():将文件描述符fd模式更改为raw
# fileno():返回一个整形的文件描述符(fd)
tty.setraw(sys.stdin.fileno())
# select():直接调用操作系统的IO接口，它监控所有带fileon()方法的文件句柄
rlist, _, _ = select.select([sys.stdin], [], [], 0.1)
if rlist:
key = sys.stdin.read(1) # 只读取一个字节
else:
key = ''
# termios该模块提供了一个用于tty I / O控制的POSIX调用的接口
# tcsetattr:从属性设置文件描述符fd的tty属性
# 参数二when: 参数确定属性何时发生更改：TCSANOW立即更改，TCSADRAIN在传输所有排队输出后更改，
# 或TCSAFLUSH在传输所有排队输出并丢弃所有排队输入后更改
termios.tcsetattr(sys.stdin, termios.TCSADRAIN, settings)
return key
speed = .2 # 线速度
turn = 1 # 角速度
def vels(speed,turn):
return "currently:\tspeed %s\tturn %s " % (speed,turn)
if __name__=="__main__":
# tcgetattr():返回包含文件描述符fd的tty属性的列表
settings = termios.tcgetattr(sys.stdin)
rospy.init_node('mrobot_teleop')
pub = rospy.Publisher('/cmd_vel', Twist, queue_size=5)
x = 0
th = 0
status = 0
count = 0
acc = 0.1
target_speed = 0 # target:目标 目标线速度
target_turn = 0 # 目标角速度
control_speed = 0
control_turn = 0
try:
print msg
print vels(speed,turn)
while(1):
key = getKey()
# 运动控制方向键（1：正方向，-1负方向）
if key in moveBindings.keys():
x = moveBindings[key][0]
th = moveBindings[key][1]
count = 0
# 速度修改键
elif key in speedBindings.keys():
speed = speed * speedBindings[key][0] # 线速度增加0.1倍
turn = turn * speedBindings[key][1] # 角速度增加0.1倍
count = 0
print vels(speed,turn)
#if (status == 14):
#print msg
status = (status + 1) % 15
# 停止键
elif key == ' ' or key == 'k' :
x = 0
th = 0
control_speed = 0
control_turn = 0
else:
count = count + 1
if count > 4:
x = 0
th = 0
if (key == '\x03'):
break
# 目标速度=速度值*方向值
target_speed = speed * x
target_turn = turn * th
# 速度限位，防止速度增减过快
if target_speed > control_speed:
control_speed = min( target_speed, control_speed + 0.02 )
elif target_speed < control_speed:
control_speed = max( target_speed, control_speed - 0.02 )
else:
control_speed = target_speed
if target_turn > control_turn:
control_turn = min( target_turn, control_turn + 0.1 )
elif target_turn < control_turn:
control_turn = max( target_turn, control_turn - 0.1 )
else:
control_turn = target_turn
# 创建并发布twist消息
twist = Twist()
twist.linear.x = control_speed;
twist.linear.y = 0;
twist.linear.z = 0
twist.angular.x = 0;
twist.angular.y = 0;
twist.angular.z = control_turn
pub.publish(twist)
except:
print e
finally:
twist = Twist()
twist.linear.x = 0; twist.linear.y = 0; twist.linear.z = 0
twist.angular.x = 0; twist.angular.y = 0; twist.angular.z = 0
pub.publish(twist)
termios.tcsetattr(sys.stdin, termios.TCSADRAIN, settings)