0

I'm trying to create a walking spider like this:
enter image description here

I considered using a SimpleMotor at the pink and red joints and control them using the rate function. But when I tried, I get an error that the function is not callable. 

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

I don't see any other functions in the pymunk API that allow controlling the joints at will. Is there really no function or am I missing something?

Basically in the run loop I want to specify rotations to the joints at certain points of time, to not just make the spider walk, but to eventually be able to use Neural Networks to allow it to experiment with various configurations of leg positions and figure out which ones can make it walk: 

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

Is it possible at all to achieve such a level of control over joints using Pymunk? To be able to stop moving the legs (without needing to put the body to sleep), or to rotate the leg joints to whatever angle the spider 'wishes to' at any point in time? Sample code would be a great help.

4

1 回答 1

0

从伺服示例中，我得到了一个提示并实现了这个基本的腿：

在此处输入图像描述

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()

s在第一次按键开始模拟后，可以通过上、左、右、下箭头键进行控制。我还确保创建的变量彼此正确链接并正确命名。

关于使关节移动到所需角度的部分尚未实现，但也许可以通过获取关节末端的 x,y 位置并使用公式计算角度然后移动电机直到它达到所需的角度。

如果有更好的方法，请通过发布答案或编辑此答案让我知道。

于 2019-03-24T08:24:22.990 回答