AP_Mount: update mount_open servo output to work for all backends

[rohan-pandeyy]

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AP_Mount: update mount_open servo output should work for all backends Issue #26892

Changes:

New function in AP_Mount_Backend

• Added a new protected function control_mount_open_servo() to the AP_Mount_Backend class which checks if the mount_open or mount2_open function is assigned and controls the corresponding servo based on the current mount mode.

Update Backend Update functions

• Modified the update() function of each mount backend (e.g., AP_Mount_Servo) to call the control_mount_open_servo() function to ensure that the open/close servo is consistently controlled across all backend implementations.

Removed redundant code

• Removed the code block in AP_Mount_Servo::update() that directly controlled the open servo using move_servo().

[rmackay9]

Hi @rohan-pandeyy,

Thanks very much for this change!

Could you modify the commit description to start with "AP_Mount: "? So change it to something like, "AP_Mount: update mount_open servo output to work for all backends"

[rmackay9]

nitpick: could you change this to check vs nullptr? so something like, "if (channel != nullptr) {". I know they're equivalent so it's not a blocker.

[rmackay9]

this section could be made more concise although it might not actually make the final flash size any smaller.

I wonder if you could put "const" before the local variables that won't change? e.g. "const uint16_t pwm_open = ..."

.. and also maybe use the terniary operator for mount_open similar to what was in the original code (but use true and false instead of "0" and "1" which really wasn't good in the original code).

[IamPete1]

Suggested change

	// move the servo to the appropriate position.
	uint16_t target_pwm = mount_open ? pwm_open : pwm_closed;
	SRV_Channels::move_servo(SRV_Channel::Aux_servo_function_t(open_chan),
	target_pwm, pwm_closed, pwm_open);
	// move the servo to the appropriate position.
	SRV_Channels::set_output_scaled(SRV_Channel::Aux_servo_function_t(open_chan), mount_open ? 1.0 : 0.0; );

Most of the function can be replaced with a set scaled. No need to get the individual output channel and mess about with PWM.

For the set scaled to work you just need to set the servo to a range output in the init somewhere:

SRV_Channels::set_range(SRV_Channel::k_mount_open, 1.0);
SRV_Channels::set_range(SRV_Channel::k_mount2_open, 1.0);

[nexton-winjeel]

If you have two mounts, this will use the same servo channel for both.

[timtuxworth]

Not sure I'm getting what this is doing. I'd want both gimbals to move in sync sometimes, but not other times depending on what I'm doing. Is that what this is?

If that's what this is, it's a great idea, but is it optional?

[rmackay9]

Yes, @nexton-winjeel is right. We should check for k_mount_open or k_mount2_open depending upon the instance of the gimbal.

[rmackay9]

@rohan-pandeyy,

Are you happy to fixup the issues raised above? If not I can take over. Txs in either case.

[rohan-pandeyy]

@rmackay9 yes you can take over regarding the issues raised above.