Thruster Processing

In the current version of SOLIS, there are several thruster set parameters that are not available in the UI. You can only add or edit them in the Configuration Manager by selecting the a Thruster Set and making changes to the parameters from that page. This page explains these parameters and how you can use them to create complex thruster set behavior. Visit the Thruster page for more information about how thrusters operate in general.

Thruster Control Modes and States

Each Thruster Control Mode describes the thruster set behavior relative to the D_PulseWidthBiasFraction. There are three options for the enumeration, E_ThrusterControlMode:

Thruster Control Mode	Enumeration
ON_PULSE	0
OFF_PULSE	1
DIFF_PULSE	2

Thrusters created in the UI default to "ON_PULSE".

The Thruster Control State is an enumeration, E_ThrusterControlState, that can be set to "ATTITUDE_CONTROL" or "MANUAL_CONTROL". "ATTITUDE_CONTROL" is the nominal state and allows a thruster set to control the attitude via pulsing. "MANUAL_CONTROL" enables you to command thrusters on/off, via sequencing, without any control in the loop.

Thruster Control State	Enumeration
ATTITUDE_CONTROL	0
MANUAL_CONTROL	1

Pulse Width Fractions

There are four parameters that control the pulse width behavior as described in the table below:

Parameter	Description	Control State Allowed
`D_MaxPWFraction`	The maximum pulse width the logic is allowed to compute	ATTITUDE_CONTROL
`D_MaxPWFractionDeadband`	The point above which the pulse width is rounded up to `D_MaxPWFraction`	ATTITUDE_CONTROL
`D_MinPWFractionDeadband`	The point below which the pulse width is rounded down to zero	ATTITUDE_CONTROL
`D_MinImpulseBit_s`	Minimum pulse width required to issue commands	ATTITUDE_CONTROL or MANUAL_CONTROL

D_MinPWFractionDeadband and D_MinImpulseBit_s perform a similar function. The thruster commanding algorithm looks at both, so in "ATTITUDE_CONTROL", the pulse width will be limited by the parameter that creates the higher threshold. D_MinImpulseBit_s enables you to limit pulse widths in "MANUAL_CONTROL" as well.

Command Cycles

The three parameters that control the overall Command Cycle behavior of "ATTITUDE_CONTROL" are described below:

Parameter	Description
`I_CmdFreqReductionFactor`	Scale factor to reduce thruster commanding frequency. For example, if base frequency is 10 Hz, setting this parameter to 2 causes the thruster commanding to cycle at 5 Hz (every other cycle). Value of 0 or 1 preserves base sample frequency.
`I_OnCmdCycles`	Number of consecutive cycles where nonzero attitude control torque command is allowed.
`I_OffCmdCycles`	Number of consecutive cycles where zero attitude control torque command is forced after on command cycles complete.