238 lines
7.6 KiB
Python
238 lines
7.6 KiB
Python
import time
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import krpc
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import math
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# ================= 配置参数 =================
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TARGET_LANDING_VELOCITY = -2.0 # 目标着陆速度 (m/s)
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SAFETY_MARGIN = 100.0 # 安全余量 (m)
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MIN_TWR_FOR_BURN = 1.1 # 开始减速的最小TWR
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# PID 控制器参数
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SPEED_KP = 0.15
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SPEED_KI = 0.05
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SPEED_KD = 0.1
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INTEGRAL_LIMIT = 0.5
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# 节流阀滤波
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ALPHA = 0.3 # 平滑系数
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DT = 0.1 # 控制周期
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# ===========================================
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conn = krpc.connect(name='Dynamic Landing')
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if not conn.space_center:
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print("No active vessel found.")
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exit()
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vessel = conn.space_center.active_vessel
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class PID:
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def __init__(self, kp, ki, kd, integral_limit=1.0):
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self.kp, self.ki, self.kd = kp, ki, kd
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self.prev_error = 0
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self.integral = 0
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self.integral_limit = integral_limit
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def update(self, error, dt):
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self.integral += error * dt
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self.integral = max(-self.integral_limit, min(self.integral_limit, self.integral))
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derivative = (error - self.prev_error) / dt
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self.prev_error = error
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return (self.kp * error) + (self.ki * self.integral) + (self.kd * derivative)
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class RocketPerformance:
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"""火箭性能计算器"""
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def __init__(self, vessel):
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self.vessel = vessel
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self.body = vessel.orbit.body
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self.g = self.body.surface_gravity # 重力加速度 (m/s²)
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def get_mass(self):
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"""获取当前质量 (kg)"""
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return self.vessel.mass
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def get_max_thrust(self):
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"""获取最大推力 (N)"""
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return self.vessel.available_thrust
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def get_twr(self):
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"""计算推重比 (Thrust-to-Weight Ratio)"""
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mass = self.get_mass()
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thrust = self.get_max_thrust()
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if mass == 0:
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return 0.0
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return thrust / (mass * self.g)
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def get_max_deceleration(self):
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"""计算最大减速度 (m/s²)"""
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twr = self.get_twr()
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# 有效减速度 = 推重比 * g - g = g * (TWR - 1)
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return self.g * (twr - 1) if twr > 1 else 0.0
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def calculate_deceleration_distance(self, current_velocity, target_velocity):
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"""
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计算从当前速度减速到目标速度需要的距离
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使用运动学公式: v² = v₀² + 2*a*d
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解得: d = (v² - v₀²) / (2*a)
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Args:
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current_velocity: 当前垂直速度 (m/s, 负值表示下降)
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target_velocity: 目标速度 (m/s, 负值表示下降)
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Returns:
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需要的减速距离 (m)
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"""
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# 如果速度为正值（上升），返回无穷大，表示不需要减速
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if current_velocity > 0:
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return float('inf')
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# 如果目标速度是一个很大的负值（表示自由落体），返回无穷大
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if target_velocity < -1000:
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return float('inf')
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# 获取当前的最大减速度（保守估计，使用平均TWR）
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max_decel = self.get_max_deceleration()
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if max_decel <= 0:
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return float('inf') # 无法减速
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# 计算需要的距离
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# 注意：速度都是负值（下降），所以 v² - v₀² 是正值
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v0_sq = current_velocity ** 2
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v_sq = target_velocity ** 2
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# 如果当前速度的绝对值小于目标速度的绝对值，说明已经足够慢了
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if abs(current_velocity) <= abs(target_velocity):
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return 0.0
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distance = (v_sq - v0_sq) / (2 * max_decel)
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return max(0, distance)
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def should_start_deceleration(self, altitude, current_velocity, target_velocity):
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"""
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判断是否应该开始减速
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Args:
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altitude: 当前高度 (m)
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current_velocity: 当前垂直速度 (m/s)
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target_velocity: 目标速度 (m/s)
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Returns:
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是否应该开始减速
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"""
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# 计算需要的减速距离
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required_distance = self.calculate_deceleration_distance(
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current_velocity, target_velocity
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)
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# 添加安全余量
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trigger_altitude = required_distance + SAFETY_MARGIN
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# 检查TWR是否足够
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twr = self.get_twr()
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should_burn = (altitude <= trigger_altitude) and (twr >= MIN_TWR_FOR_BURN)
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return should_burn, required_distance, trigger_altitude, twr
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# 初始化控制器
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speed_pid = PID(SPEED_KP, SPEED_KI, SPEED_KD, INTEGRAL_LIMIT)
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performance = RocketPerformance(vessel)
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# 节流阀平滑处理
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last_throttle = 0.0
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# 姿态控制设置
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vessel.auto_pilot.engage()
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vessel.auto_pilot.reference_frame = vessel.surface_velocity_reference_frame
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vessel.auto_pilot.target_direction = (0, -1, 0) # 始终指向速度反方向
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print("动态着陆程序启动...")
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print(f"目标着陆速度: {TARGET_LANDING_VELOCITY} m/s")
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print(f"安全余量: {SAFETY_MARGIN} m")
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# 自检
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vessel.control.throttle = 0.99
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time.sleep(0.1)
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vessel.control.throttle = 0
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burn_started = False
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while True:
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# 1. 获取飞行数据
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flight = vessel.flight(vessel.orbit.body.reference_frame)
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alt = max(0, flight.surface_altitude - 9.50) # 考虑雷达高度计偏移
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vel = flight.vertical_speed
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# 2. 获取火箭性能
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mass = performance.get_mass()
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thrust = performance.get_max_thrust()
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twr = performance.get_twr()
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max_decel = performance.get_max_deceleration()
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# 3. 判断是否应该开始减速
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should_burn, required_dist, trigger_alt, current_twr = performance.should_start_deceleration(
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alt, vel, TARGET_LANDING_VELOCITY
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)
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# 4. 姿态控制逻辑
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if alt < 30 or abs(vel) < 0.5:
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# 离地很近或速度很慢时，强制垂直向上
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vessel.auto_pilot.reference_frame = vessel.surface_reference_frame
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vessel.auto_pilot.target_direction = (1, 0, 0) # 向天
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else:
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# 正常减速阶段，锁定速度反方向
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vessel.auto_pilot.reference_frame = vessel.surface_velocity_reference_frame
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vessel.auto_pilot.target_direction = (0, -1, 0)
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# 5. 刹车控制
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if alt < 10000 and thrust > 0 and not vessel.control.brakes:
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vessel.control.brakes = True
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if alt < 30 and vessel.control.brakes:
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vessel.control.brakes = False
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# 6. 自动部署脚架
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if alt < 500:
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vessel.control.gear = True
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# 7. 动态速度规划
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if should_burn:
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burn_started = True
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target_vel = TARGET_LANDING_VELOCITY
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elif not burn_started:
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# 还没开始减速，使用自由落体或微调
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target_vel = -10000.0 # 允许快速下降
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else:
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# 已经开始减速，保持目标着陆速度
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target_vel = TARGET_LANDING_VELOCITY
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# 8. 触地检测
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if alt < 1.0 and abs(vel) < 0.5:
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vessel.control.throttle = 0
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vessel.control.sas = True
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print("已着陆！")
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break
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# 9. PID 计算
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error = target_vel - vel
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raw_throttle = speed_pid.update(error, DT)
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# 10. 节流阀滤波
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throttle = (ALPHA * raw_throttle) + ((1.0 - ALPHA) * last_throttle)
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throttle = max(0.0, min(1.0, throttle))
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last_throttle = throttle
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# 11. 执行控制
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vessel.control.throttle = throttle
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# 12. 信息输出
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status = "减速中" if burn_started else "自由落体"
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print(f"高度: {alt:6.1f}m | 速度: {vel:6.1f}m/s | 目标速: {target_vel:6.1f}m/s | "
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f"节流阀: {throttle:.2f} | TWR: {twr:.2f} | 减速距离: {required_dist:6.1f}m | "
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f"触发高度: {trigger_alt:6.1f}m | {status}")
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time.sleep(DT)
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