实战项目第29课/共30课

🤖 跳跃控制

腾空的艺术:四足机器人跳跃

📖 本课概要

腾空的艺术:四足机器人跳跃。本课将深入探讨相关理论和实现,通过Python仿真验证核心算法。

🧮 核心仿真

import math class JumpController: def __init__(self, mass=6.2, max_leg_force=150, leg_length=0.3): self.mass = mass self.g = 9.81 self.max_force = max_leg_force self.leg_length = leg_length def compute_jump_params(self, target_height): v_needed = math.sqrt(2 * self.g * target_height) impulse = self.mass * v_needed push_time = impulse / self.max_force push_distance = 0.5 * (self.max_force/self.mass - self.g) * push_time**2 return v_needed, impulse, push_time, push_distance def simulate_jump(self, target_height=0.1, dt=0.0001): v_needed, impulse, push_time, push_dist = self.compute_jump_params(target_height) z = 0 z_dot = 0 phase = 'push' t = 0 history = [] peak_height = 0 while t < 2.0: if phase == 'push': F = self.max_force z_ddot = F / self.mass - self.g z_dot += z_ddot * dt z += z_dot * dt if z_dot >= v_needed: phase = 'flight' elif phase == 'flight': z_ddot = -self.g z_dot += z_ddot * dt z += z_dot * dt peak_height = max(peak_height, z) if z <= 0 and z_dot < 0: phase = 'landing' z = 0 elif phase == 'landing': # Spring-damper landing F = 2000 * (-z) + 100 * (-z_dot) if F < 0: F = 0 z_ddot = F / self.mass - self.g z_dot += z_ddot * dt z += z_dot * dt if abs(z) < 0.001 and abs(z_dot) < 0.01: break if int(t*10000) % 200 == 0: history.append((t, z, z_dot, phase)) t += dt return history, peak_height jc = JumpController() print("=" * 55) print(" Jump Control Simulation") print("=" * 55) # Jump parameters print(f"\n [Jump Parameters]") for h in [0.02, 0.05, 0.10, 0.15, 0.20, 0.30]: v, imp, pt, pd = jc.compute_jump_params(h) feasible = pd < jc.leg_length * 0.8 print(f" h={h*100:.0f}cm: v={v:.2f}m/s impulse={imp:.1f}Ns " f"push_time={pt*1000:.1f}ms push_dist={pd*1000:.1f}mm {'OK' if feasible else 'INFEASIBLE'}") # Jump simulation print(f"\n [Jump Simulation: 10cm target]") hist, peak = jc.simulate_jump(target_height=0.10) for t, z, v, phase in hist: print(f" t={t:.4f}s z={z*1000:.1f}mm v={v*1000:.1f}mm/s [{phase}]") print(f" Peak height: {peak*100:.2f}cm") # Max jump height print(f"\n [Maximum Jump Height]") max_h = 0 for h_cm in range(1, 50): h = h_cm / 100.0 v, imp, pt, pd = jc.compute_jump_params(h) if pd < jc.leg_length * 0.8 and pt > 0.001: max_h = h print(f" Max feasible jump: {max_h*100:.0f}cm (with max_force={jc.max_force}N)") print() print(" OK - Jump control simulation complete")

仿真结果:

======================================================= Jump Control Simulation ======================================================= [Jump Parameters] h=2cm: v=0.63m/s impulse=3.9Ns push_time=25.9ms push_dist=4.8mm OK h=5cm: v=0.99m/s impulse=6.1Ns push_time=40.9ms push_dist=12.1mm OK h=10cm: v=1.40m/s impulse=8.7Ns push_time=57.9ms push_dist=24.1mm OK h=15cm: v=1.72m/s impulse=10.6Ns push_time=70.9ms push_dist=36.2mm OK h=20cm: v=1.98m/s impulse=12.3Ns push_time=81.9ms push_dist=48.2mm OK h=30cm: v=2.43m/s impulse=15.0Ns push_time=100.3ms push_dist=72.3mm OK [Jump Simulation: 10cm target] t=0.0000s z=0.0mm v=1.4mm/s [push] t=0.0201s z=2.9mm v=290.5mm/s [push] t=0.0400s z=11.6mm v=576.8mm/s [push] t=0.0600s z=26.0mm v=864.5mm/s [push] t=0.0800s z=46.2mm v=1152.1mm/s [push] t=0.1000s z=72.0mm v=1374.5mm/s [flight] t=0.1200s z=97.6mm v=1178.3mm/s [flight] t=0.1400s z=119.2mm v=982.1mm/s [flight] t=0.1601s z=136.9mm v=784.9mm/s [flight] t=0.1801s z=150.6mm v=588.7mm/s [flight] t=0.2001s z=160.4mm v=392.5mm/s [flight] t=0.2201s z=166.3mm v=196.3mm/s [flight] t=0.2401s z=168.3mm v=0.1mm/s [flight] t=0.2601s z=166.3mm v=-196.1mm/s [flight] t=0.2801s z=160.4mm v=-392.3mm/s [flight] t=0.3001s z=150.6mm v=-588.5mm/s [flight] t=0.3201s z=136.8mm v=-784.7mm/s [flight] t=0.3401s z=119.2mm v=-980.9mm/s [flight] t=0.3601s z=97.6mm v=-1177.1mm/s [flight] t=0.3801s z=72.1mm v=-1373.3mm/s [flight] t=0.4001s z=42.6mm v=-1569.5mm/s [flight] t=0.4201s z=9.3mm v=-1765.7mm/s [flight] t=0.4401s z=-24.6mm v=-1504.2mm/s [landing] t=0.4601s z=-50.1mm v=-1043.2mm/s [landing] t=0.4801s z=-66.4mm v=-595.5mm/s [landing] t=0.5001s z=-74.3mm v=-206.3mm/s [landing] t=0.5201s z=-75.2mm v=98.0mm/s [landing] t=0.5401s z=-71.0mm v=307.7mm/s [landing] t=0.5601s z=-63.5mm v=425.9mm/s [landing] t=0.5801s z=-54.4mm v=465.0mm/s [landing] t=0.6001s z=-45.3mm v=442.6mm/s [landing] t=0.6201s z=-37.0mm v=378.0mm/s [landing] t=0.6401s z=-30.3mm v=289.9mm/s [landing] t=0.6601s z=-25.5mm v=194.5mm/s [landing] t=0.6801s z=-22.5mm v=104.2mm/s [landing] t=0.7001s z=-21.2mm v=27.4mm/s [landing] t=0.7201s z=-21.3mm v=-31.1mm/s [landing] t=0.7401s z=-22.3mm v=-70.2mm/s [landing] t=0.7601s z=-24.0mm v=-90.8mm/s [landing] t=0.7801s z=-25.9mm v=-95.8mm/s [landing] t=0.8001s z=-27.7mm v=-88.9mm/s [landing] t=0.8201s z=-29.4mm v=-74.3mm/s [landing] t=0.8401s z=-30.7mm v=-55.6mm/s [landing] t=0.8601s z=-31.6mm v=-35.9mm/s [landing] t=0.8801s z=-32.1mm v=-17.8mm/s [landing] t=0.9001s z=-32.3mm v=-2.7mm/s [landing] t=0.9201s z=-32.3mm v=8.5mm/s [landing] t=0.9401s z=-32.0mm v=15.7mm/s [landing] t=0.9601s z=-31.7mm v=19.2mm/s [landing] t=0.9801s z=-31.3mm v=19.6mm/s [landing] t=1.0001s z=-30.9mm v=17.8mm/s [landing] t=1.0201s z=-30.6mm v=14.5mm/s [landing] t=1.0401s z=-30.3mm v=10.6mm/s [landing] t=1.0601s z=-30.1mm v=6.6mm/s [landing] t=1.0801s z=-30.0mm v=2.9mm/s [landing] t=1.1001s z=-30.0mm v=-0.0mm/s [landing] t=1.1201s z=-30.0mm v=-2.1mm/s [landing] t=1.1401s z=-30.1mm v=-3.4mm/s [landing] t=1.1601s z=-30.2mm v=-4.0mm/s [landing] t=1.1801s z=-30.3mm v=-4.0mm/s [landing] t=1.2001s z=-30.3mm v=-3.5mm/s [landing] t=1.2201s z=-30.4mm v=-2.8mm/s [landing] t=1.2401s z=-30.4mm v=-2.0mm/s [landing] t=1.2601s z=-30.5mm v=-1.2mm/s [landing] t=1.2801s z=-30.5mm v=-0.5mm/s [landing] t=1.3001s z=-30.5mm v=0.1mm/s [landing] t=1.3201s z=-30.5mm v=0.5mm/s [landing] t=1.3401s z=-30.5mm v=0.7mm/s [landing] t=1.3601s z=-30.5mm v=0.8mm/s [landing] t=1.3801s z=-30.4mm v=0.8mm/s [landing] t=1.4001s z=-30.4mm v=0.7mm/s [landing] t=1.4201s z=-30.4mm v=0.5mm/s [landing] t=1.4401s z=-30.4mm v=0.4mm/s [landing] t=1.4601s z=-30.4mm v=0.2mm/s [landing] t=1.4801s z=-30.4mm v=0.1mm/s [landing] t=1.5001s z=-30.4mm v=-0.0mm/s [landing] t=1.5201s z=-30.4mm v=-0.1mm/s [landing] t=1.5401s z=-30.4mm v=-0.2mm/s [landing] t=1.5601s z=-30.4mm v=-0.2mm/s [landing] t=1.5801s z=-30.4mm v=-0.2mm/s [landing] t=1.6001s z=-30.4mm v=-0.1mm/s [landing] t=1.6201s z=-30.4mm v=-0.1mm/s [landing] t=1.6401s z=-30.4mm v=-0.1mm/s [landing] t=1.6601s z=-30.4mm v=-0.0mm/s [landing] t=1.6801s z=-30.4mm v=-0.0mm/s [landing] t=1.7001s z=-30.4mm v=0.0mm/s [landing] t=1.7201s z=-30.4mm v=0.0mm/s [landing] t=1.7401s z=-30.4mm v=0.0mm/s [landing] t=1.7601s z=-30.4mm v=0.0mm/s [landing] t=1.7801s z=-30.4mm v=0.0mm/s [landing] t=1.8001s z=-30.4mm v=0.0mm/s [landing] t=1.8201s z=-30.4mm v=0.0mm/s [landing] t=1.8401s z=-30.4mm v=0.0mm/s [landing] t=1.8601s z=-30.4mm v=0.0mm/s [landing] t=1.8801s z=-30.4mm v=0.0mm/s [landing] t=1.9001s z=-30.4mm v=-0.0mm/s [landing] t=1.9201s z=-30.4mm v=-0.0mm/s [landing] t=1.9401s z=-30.4mm v=-0.0mm/s [landing] t=1.9601s z=-30.4mm v=-0.0mm/s [landing] t=1.9801s z=-30.4mm v=-0.0mm/s [landing] Peak height: 16.83cm [Maximum Jump Height] Max feasible jump: 49cm (with max_force=150N) OK - Jump control simulation complete

📊 项目评估指标

指标目标值说明
行走速度≥0.5 m/s不同地形加权平均
稳定裕度≥10mm全程最小值
能量效率CoT≤0.5运输成本
恢复成功率≥90%中等推力恢复
地形适应≥4种flat/rough/slope/stairs

📐 跳跃动力学

四足机器人跳跃的三个阶段:

1. 蓄力阶段(Stance)

腿压缩,储存弹性势能:

F = m·(a + g) ≤ Fmax
vtakeoff = sqrt(2·g·htarget)

2. 腾空阶段(Flight)

仅受重力影响,CoM做抛物线运动:

z(t) = z0 + v0·t - 0.5·g·t2

3. 着陆阶段(Landing)

吸收冲击,恢复站立。

💡 连续跳跃控制

连续跳跃需要精确的时序控制:

  1. 着陆时立即检测触地
  2. 压缩阶段:弹簧蓄力
  3. 释放时机:当腿部压缩到最大时
  4. 腾空阶段:调整姿态
  5. 预判着陆:准备触地缓冲

MIT Cheetah实现了连续3Hz跳跃,高度10-30cm。

🔄 跳跃方向控制

通过改变推力方向控制跳跃方向:

Fdirection = Ftotal · [sin(α), cos(α)]
α = atan2(vx,target, vz,target)

前跳:推力略向前倾;侧跳:左右腿不对称推力;旋转跳:加偏航力矩。

📚 本课参考与延伸

核心概念回顾

实现建议

  1. 先用Python/MATLAB验证算法正确性
  2. 然后在物理引擎(PyBullet/MuJoCo)中测试
  3. 最后在真实机器人上部署,使用域随机化增强鲁棒性

常见问题

📝 练习

  1. 修改仿真参数,观察系统行为的变化。
  2. 实现本课核心算法的改进版本。
  3. 将本课方法与其他课的方法组合,设计复合控制器。
  4. 分析算法在不同条件下的鲁棒性。
  5. 设计实验验证仿真结果的正确性。
🏆
跳跃大师

完成四足机器人跳跃控制仿真

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