rc.trigger_collision failure

[hazidh]

Hello, I noticed that you updated some APIs a few days ago. My original rc.trigger_collision was capable of triggering a collision. However, after the update, it was no longer able to produce the collision effect. But I tried rc.trigger_impulse_collision and it was able to generate a normal collision.

[tmori]

Hello, I noticed that you updated some APIs a few days ago. My original rc.trigger_collision was capable of triggering a collision. However, after the update, it was no longer able to produce the collision effect. But I tried rc.trigger_impulse_collision and it was able to generate a normal collision.

Yes, as you've noticed, the conventional rc.trigger_collision has been deprecated. Please use rc.trigger_impulse_collision instead.

[hazidh]

Hello, I noticed that you updated some APIs a few days ago. My original rc.trigger_collision was capable of triggering a collision. However, after the update, it was no longer able to produce the collision effect. But I tried rc.trigger_impulse_collision and it was able to generate a normal collision.

Yes, as you've noticed, the conventional rc.trigger_collision has been deprecated. Please use rc.trigger_impulse_collision instead.
Thank you for your reply. However, the effect produced by using rc.trigger_impulse_collision is not very satisfactory for me. I was simulating an unmanned aircraft colliding with a static cube, and the resulting effect was unstable just like in the video.

try (Vector3Type target_velocity = new Vector3Type(ArenaType.Confined, 0, 0, 0);
                         Vector3Type target_angular_velocity = new Vector3Type(ArenaType.Confined, 0, 0, 0);
                         Vector3Type target_euler = new Vector3Type(ArenaType.Confined, 0, 0, 0);
                         Vector3Type target_inertia = new Vector3Type(ArenaType.Confined, 0, 0, 0);
                         Vector3Type self_contact_pos_v =
                                 com.po.hakoniwa.utils.MathUtils.vectorTranslateVector3Type(ArenaType.Confined,self_contact_pos.get(i));
                         Vector3Type target_contact_pos_v =
                                 com.po.hakoniwa.utils.MathUtils.vectorTranslateVector3Type(ArenaType.Confined,target_contact_pos.get(i));
                         Vector3Type normal_contact_pos_v =
                                 com.po.hakoniwa.utils.MathUtils.vectorTranslateVector3Type(ArenaType.Confined,normal_contact_pos.get(i));){
                        droneServiceAppState.trigger_impulse_collision(index,true,target_velocity,target_angular_velocity,
                                target_euler,self_contact_pos_v,target_contact_pos_v,target_inertia,normal_contact_pos_v,100,1);
                    }

20250716_101823.mp4

[hazidh]

Can you re-enable rc.trigger_impulse_collision?

[tmori]

Can you re-enable rc.trigger_impulse_collision?

I'm sorry, but we generally don't re-enable the old version of collision unless there's a compelling reason.
Could you please review the arguments of trigger_impulse_collision()?
In particular, would it be possible to resolve the issue by adjusting parameters like mass or restitution?

[hazidh]

Because the trigger_impulse_collision function has many parameters for the user, making it difficult to adjust, or could you explain the parameters of the trigger_impulse_collision method, such as target_angular_velocity, target_euler, self_contact_pos_v, target_contact_pos_v, and the coordinate system of normal (is it the NED coordinate system or the right-handed coordinate system)? I am unable to achieve good results by adjusting mass or restitution.
Also, could you activate

ANGLE_CONTROL_ENABLE            0
ALT_SPD_CONTROL_ENABLE          0
ANGLE_RATE_CONTROL_ENABLE       0

The control of these three parameters occurs during the flight process. For instance, when I want to switch to a different mode during the flight.

ANGLE_CONTROL_ENABLE            1
ALT_SPD_CONTROL_ENABLE          0
ANGLE_RATE_CONTROL_ENABLE       0

[tmori]

Because the trigger_impulse_collision function has many parameters for the user, making it difficult to adjust, or could you explain the parameters of the trigger_impulse_collision method, such as target_angular_velocity, target_euler, self_contact_pos_v, target_contact_pos_v, and the coordinate system of normal (is it the NED coordinate system or the right-handed coordinate system)? I am unable to achieve good results by adjusting mass or restitution.

the frame is ROS coordinate system.

api arguments brief explanation is here:

- self_velocity:
    - unit: m/s
    - description: self velocity
- self_angular_velocity:
    - unit: rad/s
    - description: self angular velocity
- self_euler:
    - unit: rad
    - description: {0,0,0} if you use self body frame(recommended)
- target_velocity:
    - unit: m/s
    - description: target velocity
- target_angular_velocity:
    - unit: rad/s
    - description: target angular velocity
- target_euler:
    - unit: rad
    - description: target euler angle
- self_contact:
    - unit: m
    - description: self contact vector, from self center to contact = contact_point - center_point in body frame
- target_contact:
    - unit: m
    - description: vector from target center to contact = contact_point - other_center_point in body frame
- self_mass:
    - unit: kg
    - description: self mass
- target_mass:
    - unit: kg
    - description: target mass
- self_inertia:
    - unit: kg*m^2
    - description: diagonal elements of the inertia tensor of the self in self body frame(euler)
- target_inertia:
    - unit: kg*m^2
    - description: diagonal elements of the inertia tensor of the target in target body frame(euler)
- normal:
    - unit: none
    - description: normal vector of the contact surface (n and -n give the same result, don't care the +/- direction)
- restitution_coefficient:
    - unit: none
    - description: 0.0-1.0

[tmori]

Also, could you activate

ANGLE_CONTROL_ENABLE 0
ALT_SPD_CONTROL_ENABLE 0
ANGLE_RATE_CONTROL_ENABLE 0
The control of these three parameters occurs during the flight process. For instance, when I want to switch to a different mode during the flight.

ANGLE_CONTROL_ENABLE 1
ALT_SPD_CONTROL_ENABLE 0
ANGLE_RATE_CONTROL_ENABLE 0

Thank you for your suggestion.

Currently, we support only two control modes, which correspond to specific parameter combinations in the configuration file:

Flight Mode	ANGLE_CONTROL_ENABLE	ALT_SPD_CONTROL_ENABLE	ANGLE_RATE_CONTROL_ENABLE	Description
mode = 0 (ATTI)	1	1	0	Attitude and altitude speed control enabled
mode = 1 (GPS)	0	0	0	Manual-style mode (attitude and altitude control disabled)

These modes can be switched during flight using the following API:

// Switch flight mode (0: ATTI, 1: GPS)
int drone_service_rc_put_mode_change_button(int index, int value);

To retrieve the current mode:

// Get current flight mode
int drone_service_rc_get_flight_mode(int index, int* mode);

⚠️ Important: Other combinations of control parameters (e.g., enabling only angle control or only altitude control, or using ANGLE_RATE_CONTROL_ENABLE) are not implemented in the current system.
Only the two modes shown above are available at this time.

---

[hazidh]

因为 trigger_impulse_collision 函数为用户提供了许多参数，使得调整起来很困难，或者您能解释一下 trigger_impulse_collision 方法的参数，比如 target_angular_velocity、target_euler、self_contact_pos_v、target_contact_pos_v，以及法线坐标系（是 NED 坐标系还是右手坐标系）？我无法通过调整质量或恢复来获得良好的结果。

框架为 ROS 坐标系。

API 参数的简要说明如下：

- self_velocity:
    - unit: m/s
    - description: self velocity
- self_angular_velocity:
    - unit: rad/s
    - description: self angular velocity
- self_euler:
    - unit: rad
    - description: {0,0,0} if you use self body frame(recommended)
- target_velocity:
    - unit: m/s
    - description: target velocity
- target_angular_velocity:
    - unit: rad/s
    - description: target angular velocity
- target_euler:
    - unit: rad
    - description: target euler angle
- self_contact:
    - unit: m
    - description: self contact vector, from self center to contact = contact_point - center_point in body frame
- target_contact:
    - unit: m
    - description: vector from target center to contact = contact_point - other_center_point in body frame
- self_mass:
    - unit: kg
    - description: self mass
- target_mass:
    - unit: kg
    - description: target mass
- self_inertia:
    - unit: kg*m^2
    - description: diagonal elements of the inertia tensor of the self in self body frame(euler)
- target_inertia:
    - unit: kg*m^2
    - description: diagonal elements of the inertia tensor of the target in target body frame(euler)
- normal:
    - unit: none
    - description: normal vector of the contact surface (n and -n give the same result, don't care the +/- direction)
- restitution_coefficient:
    - unit: none
    - description: 0.0-1.0

Thank you for your reply. I have learned that drones have a posture mode and a height-fixing mode, that is
ANGLE_CONTROL_ENABLE 1
ALT_SPD_CONTROL_ENABLE 0
ANGLE_RATE_CONTROL_ENABLE 0
Could this be integrated into the back part?

[tmori]

At this time, we do not have any plans to support that mode.
However, we may consider it in the future if we have the capacity, so please feel free to open an issue to track the request.

[hazidh]

https://github.com/user-attachments/assets/27d1ab52-47c8-4786-b815-c4df200a9f2d
Hello, I think the "trigger_impulse_collision" parameter is unstable. It involves the linear velocity state. Moreover, I haven't been able to find a suitable state parameter at present. Could we keep the "rc.trigger_collision" interface?

[tmori]

please see our sample code of unity.

https://github.com/hakoniwalab/hakoniwa-unity-drone/blob/main/simulation/Assets/Scripts/Drone/DroneCollision.cs

[hazidh]

please see our sample code of unity.

https://github.com/hakoniwalab/hakoniwa-unity-drone/blob/main/simulation/Assets/Scripts/Drone/DroneCollision.cs

Thank you for your reply. I have indeed benefited a lot from it. However, my current test result is as shown in the video. Before the collision, the speed of the drone in that direction was 2.46 m/s, but the impact effect was very significant. Why is that?

try (Vector3Type target_velocity = new Vector3Type(ArenaType.Confined, 0, 0, 0);
                         Vector3Type target_angular_velocity = new Vector3Type(ArenaType.Confined, 0, 0, 0);
                         Vector3Type target_euler = new Vector3Type(ArenaType.Confined, 0, 0, 0);
                         Vector3Type target_inertia = new Vector3Type(ArenaType.Confined, 0, 0, 0);
                         Vector3Type self_contact_pos_v =
                                 com.po.hakoniwa.utils.MathUtils.vectorTranslateVector3Type(ArenaType.Confined, self_contact_pos.get(i));
                         Vector3Type target_contact_pos_v =
                                 com.po.hakoniwa.utils.MathUtils.vectorTranslateVector3Type(ArenaType.Confined, target_contact_pos.get(i));
                         Vector3Type normal_contact_pos_v =
                                 com.po.hakoniwa.utils.MathUtils.vectorTranslateVector3Type(ArenaType.Confined, normal_contact_pos.get(i).normalize().negate());) {
                        droneServiceAppState.trigger_impulse_collision(index, true, target_velocity, target_angular_velocity,
                                target_euler, self_contact_pos_v, target_contact_pos_v, target_inertia, normal_contact_pos_v, 0.71, 0.4);
                    }

20250716_160243.mp4

[hazidh]

Hello, could you please check for me if the collision effect is functioning properly? Through my experiments, I found that the drone's speed reached 1m/s only when the "right" button was pressed and then released. At this point, the collision effect was still normal. However, when the speed reached 3m/s, the drone flew off. Is this normal? The cube is a static object. I'm looking forward to your reply!

try (Vector3Type target_velocity = com.po.hakoniwa.utils.MathUtils.ConvertToRosVector(ArenaType.Confined,new Vector3f(0,0,0));
                         Vector3Type target_angular_velocity = com.po.hakoniwa.utils.MathUtils.ConvertToRosAngular(ArenaType.Confined,new Vector3f(0,0,0));
                         Vector3Type target_euler = com.po.hakoniwa.utils.MathUtils.ConvertToRosAngular(ArenaType.Confined,new Vector3f(0,0,0));
                         Vector3Type target_inertia = new Vector3Type(ArenaType.Confined, 0,0,0);
                         Vector3Type self_contact_pos_v =
                                 com.po.hakoniwa.utils.MathUtils.ConvertToRosVector(ArenaType.Confined, self_contact_pos.get(i));
                         Vector3Type target_contact_pos_v =
                                 com.po.hakoniwa.utils.MathUtils.ConvertToRosVector(ArenaType.Confined, target_contact_pos.get(i));
                         Vector3Type normal_contact_pos_v =
                                 com.po.hakoniwa.utils.MathUtils.ConvertToRosVector(ArenaType.Confined, normal_contact_pos.get(i));) {
                        droneServiceAppState.trigger_impulse_collision(index, true, target_velocity, target_angular_velocity,
                                target_euler, self_contact_pos_v, target_contact_pos_v,
                                target_inertia, normal_contact_pos_v, 0.71, 0);
                    }

20250717_092259.zip

[tmori]

Sorry, I don't have time to check it right now.

However, you can find information regarding the physical explanation of collisions here:
https://github.com/toppers/hakoniwa-drone-core/blob/main/docs/api/physics/Collision.md

Please note that this pertains to the physics module.

hakoniwa-drone-core/include/physics/body_physics.hpp

Line 95 in 1182cbe

/**

On the service side, it basically just calls this function after converting the coordinate frame (from ROS to NED).
If the collision target object is static, it calls the function like this:

const auto& collision = input.impulse_collision;

// self parameters in Self Body Frame
drone_physics::VectorType self_velocity = this->velocityBodyFrame;
auto self_contact = drone_physics::body_vector_from_ground(collision.self_contact_vector, angle);
drone_physics::VelocityType self_angular_velocity = angularVelocityBodyFrame;

// target velocity and contact in Self Body Frame
// the input is ground frame.
auto target_velocity = drone_physics::body_vector_from_ground(collision.target_velocity, angle);
auto target_contact = drone_physics::body_vector_from_ground(collision.target_contact_vector, angle);
auto target_angular_velocity = drone_physics::body_vector_from_ground(collision.target_angular_velocity, angle);
auto target_mass = collision.target_mass;
auto target_inertia = collision.target_inertia;

auto normal = target_velocity - self_velocity;

J = drone_physics::impulse_by_collision(
    self_velocity,
    self_angular_velocity,
    { 0, 0, 0 }, 
    target_velocity, 
    self_contact, 
    param_mass, 
    { param_cx, param_cy, param_cz },
    normal,
    collision.restitution_coefficient);

[hazidh]

coordicates are ALL in one (self body) frameDoes this mean that using local coordinates, the self-coordinate of the drone becomes the "own coordinate" of the drone, and the target-coordinate of the box becomes the "own coordinate" of the box?