Question

我正在尝试创建一个像这样的行走蜘蛛：

我考虑过在粉红色和红色关节处使用SimpleMotor，并使用rate功能对其进行控制。但是，当我尝试时，出现错误，表明该函数不可调用。

self.motorJoint1.rate(0.0) TypeError: 'float' object is not callable

我在pymunk API中看不到其他任何可以随意控制关节的功能。真的没有功能吗，或者我缺少什么？

基本上是在运行循环中，我想指定在特定时间点关节的旋转，不仅要使蜘蛛行走，而且最终要能够使用神经网络来试验腿的各种姿势并找出哪些可以使之行走：

angle1 = 30
angle2 = 10
redJoint1.rotate(angle1)
pinkJoint2.rotate(angle2)
if angle1 < 50:
    angle1 = angle1 + 1

使用Pymunk是否有可能达到对关节的这种控制水平？为了能够停止移动腿（无需让身体入睡），或在任何时间点将腿关节旋转到蜘蛛“希望”的任何角度？示例代码将提供很大的帮助。

Answer 1

在servo example中，我做了一个提示并实现了这一基本步骤：

import sys

import pygame
from pygame.locals import USEREVENT, QUIT, KEYDOWN, KEYUP, K_s, K_r, K_q, K_ESCAPE, K_UP, K_DOWN, K_RIGHT, K_LEFT
from pygame.color import THECOLORS

import pymunk
from pymunk import Vec2d
import pymunk.pygame_util

class Simulator(object):

    def __init__(self):
        self.display_flags = 0
        self.display_size = (600, 600)

        self.space = pymunk.Space()
        self.space.gravity = (0.0, -1900.0)
        #self.space.damping = 0.999 # to prevent it from blowing up.

        # Pymunk physics coordinates start from the lower right-hand corner of the screen.
        self.ground_y = 100
        ground = pymunk.Segment(self.space.static_body, (5, self.ground_y), (595, self.ground_y), 1.0)
        ground.friction = 1.0
        self.space.add(ground)

        self.screen = None

        self.draw_options = None

    def reset_bodies(self):
        for body in self.space.bodies:
            if not hasattr(body, 'start_position'):
                continue
            body.position = Vec2d(body.start_position)
            body.force = 0, 0
            body.torque = 0
            body.velocity = 0, 0
            body.angular_velocity = 0
            body.angle = body.start_angle

    def draw(self):        
        self.screen.fill(THECOLORS["white"])### Clear the screen        
        self.space.debug_draw(self.draw_options)### Draw space        
        pygame.display.flip()### All done, lets flip the display

    def main(self):
        pygame.init()
        self.screen = pygame.display.set_mode(self.display_size, self.display_flags)
        width, height = self.screen.get_size()
        self.draw_options = pymunk.pygame_util.DrawOptions(self.screen)

        def to_pygame(p):            
            return int(p.x), int(-p.y+height) #Small hack to convert pymunk to pygame coordinates
        def from_pygame(p):
            return to_pygame(p)

        clock = pygame.time.Clock()
        running = True
        font = pygame.font.Font(None, 16)

        # Create the spider
        chassisXY = Vec2d(self.display_size[0]/2, self.ground_y+100)
        chWd = 70; chHt = 50
        chassisMass = 10

        legWd_a = 50; legHt_a = 5
        legWd_b = 100; legHt_b = 5
        legMass = 1
        relativeAnguVel = 0

        #---chassis
        chassis_b = pymunk.Body(chassisMass, pymunk.moment_for_box(chassisMass, (chWd, chHt)))
        chassis_b.position = chassisXY
        chassis_shape = pymunk.Poly.create_box(chassis_b, (chWd, chHt))
        chassis_shape.color = 200, 200, 200
        print("chassis position");print(chassis_b.position)

        #---first left leg a
        leftLeg_1a_body = pymunk.Body(legMass, pymunk.moment_for_box(legMass, (legWd_a, legHt_a)))
        leftLeg_1a_body.position = chassisXY - ((chWd/2)+(legWd_a/2), 0)
        leftLeg_1a_shape = pymunk.Poly.create_box(leftLeg_1a_body, (legWd_a, legHt_a))        
        leftLeg_1a_shape.color = 255, 0, 0

        #---first left leg b
        leftLeg_1b_body = pymunk.Body(legMass, pymunk.moment_for_box(legMass, (legWd_b, legHt_b)))
        leftLeg_1b_body.position = leftLeg_1a_body.position - ((legWd_a/2)+(legWd_b/2), 0)
        leftLeg_1b_shape = pymunk.Poly.create_box(leftLeg_1b_body, (legWd_b, legHt_b))        
        leftLeg_1b_shape.color = 0, 255, 0        

        #---first right leg a
        rightLeg_1a_body = pymunk.Body(legMass, pymunk.moment_for_box(legMass, (legWd_a, legHt_a)))
        rightLeg_1a_body.position = chassisXY + ((chWd/2)+(legWd_a/2), 0)
        rightLeg_1a_shape = pymunk.Poly.create_box(rightLeg_1a_body, (legWd_a, legHt_a))        
        rightLeg_1a_shape.color = 255, 0, 0        

        #---first right leg b
        rightLeg_1b_body = pymunk.Body(legMass, pymunk.moment_for_box(legMass, (legWd_b, legHt_b)))
        rightLeg_1b_body.position = rightLeg_1a_body.position + ((legWd_a/2)+(legWd_b/2), 0)
        rightLeg_1b_shape = pymunk.Poly.create_box(rightLeg_1b_body, (legWd_b, legHt_b))        
        rightLeg_1b_shape.color = 0, 255, 0     

        #---link left leg b with left leg a       
        pj_ba1left = pymunk.PinJoint(leftLeg_1b_body, leftLeg_1a_body, (legWd_b/2,0), (-legWd_a/2,0))#anchor point coordinates are wrt the body; not the space
        motor_ba1Left = pymunk.SimpleMotor(leftLeg_1b_body, leftLeg_1a_body, relativeAnguVel)
        #---link left leg a with chassis
        pj_ac1left = pymunk.PinJoint(leftLeg_1a_body, chassis_b, (legWd_a/2,0), (-chWd/2, 0))
        motor_ac1Left = pymunk.SimpleMotor(leftLeg_1a_body, chassis_b, relativeAnguVel)
        #---link right leg b with right leg a       
        pj_ba1Right = pymunk.PinJoint(rightLeg_1b_body, rightLeg_1a_body, (-legWd_b/2,0), (legWd_a/2,0))#anchor point coordinates are wrt the body; not the space
        motor_ba1Right = pymunk.SimpleMotor(rightLeg_1b_body, rightLeg_1a_body, relativeAnguVel)
        #---link right leg a with chassis
        pj_ac1Right = pymunk.PinJoint(rightLeg_1a_body, chassis_b, (-legWd_a/2,0), (chWd/2, 0))
        motor_ac1Right = pymunk.SimpleMotor(rightLeg_1a_body, chassis_b, relativeAnguVel)              

        self.space.add(chassis_b, chassis_shape) 
        self.space.add(leftLeg_1a_body, leftLeg_1a_shape, rightLeg_1a_body, rightLeg_1a_shape) 
        self.space.add(leftLeg_1b_body, leftLeg_1b_shape, rightLeg_1b_body, rightLeg_1b_shape) 
        self.space.add(pj_ba1left, motor_ba1Left, pj_ac1left, motor_ac1Left)  
        self.space.add(pj_ba1Right, motor_ba1Right, pj_ac1Right, motor_ac1Right)      

        #---prevent collisions with ShapeFilter
        shape_filter = pymunk.ShapeFilter(group=1)
        chassis_shape.filter = shape_filter
        leftLeg_1a_shape.filter = shape_filter
        rightLeg_1a_shape.filter = shape_filter
        leftLeg_1b_shape.filter = shape_filter
        rightLeg_1b_shape.filter = shape_filter        


        simulate = False
        rotationRate = 2
        while running:
            for event in pygame.event.get():
                if event.type == QUIT or (event.type == KEYDOWN and event.key in (K_q, K_ESCAPE)):
                    #running = False
                    sys.exit(0)
                elif event.type == KEYDOWN and event.key == K_s:
                    # Start/stop simulation.
                    simulate = not simulate
                elif event.type == KEYDOWN and event.key == K_r:
                    # Reset.
                    # simulate = False
                    self.reset_bodies()
                elif event.type == KEYDOWN and event.key == K_UP:
                    motor_ba1Left.rate = rotationRate
                elif event.type == KEYDOWN and event.key == K_DOWN:
                    motor_ba1Left.rate = -rotationRate
                elif event.type == KEYDOWN and event.key == K_LEFT:
                    motor_ac1Left.rate = rotationRate
                elif event.type == KEYDOWN and event.key == K_RIGHT:
                    motor_ac1Left.rate = -rotationRate                    
                elif event.type == KEYUP:
                    motor_ba1Left.rate = 0
                    motor_ac1Left.rate = 0

            self.draw()

            ### Update physics
            fps = 50
            iterations = 25
            dt = 1.0/float(fps)/float(iterations)
            if simulate:
                for x in range(iterations): # 10 iterations to get a more stable simulation
                    self.space.step(dt)

            pygame.display.flip()
            clock.tick(fps)

if __name__ == '__main__':
    sim = Simulator()
    sim.main()

在首先按下s键开始模拟之后，可以使用向上，向左，向右和向下箭头键控制它。我还确保变量创建正确，彼此正确链接并命名正确。

关于使关节移动到所需角度的部分尚未实现，但也许可以通过取关节末端的x，y位置并使用公式计算角度然后移动来计算直到达到所需角度为止。

如果有更好的方法，请发布答案或编辑答案以告知我。

如何随意旋转pymunk关节？

1 个答案: