Tekkotsu: MotionManager Class Reference

Since Main and Motion run as separate processes, they could potentially try to access the same motion command at the same time, leading to unpredictable behavior. The MotionManager enforces a set of locks to serialize access to the MotionCommands. Although you could call checkoutMotion() and checkinMotion() directly, it is instead recommended to use MMAccessor to automatically handle casting and checkin for you.

The other problem is that we are sharing the memory holding MotionCommands between processes. MotionManager will do the necessary magic behind the scenes to distribute new MotionCommands to all the involved processes (currently just Main and Motion)
You can create and add a new motion in one line:

  // type A: prunable motions are automatically removed when completed:
  motman->addPrunableMotion( SharedObject<YourMC>([arg1,...]) [, priority ] );

  // type B: persistent motions are removed only when you explicitly request it:
  MC_ID id = motman->addPersistentMotion( SharedObject<YourMC>([arg1,...]) [, priority ] );
  // then later: motman->removeMotion(id);

The priority level can be changed later via setPriority(), and there are symbolic values defined in kIgnoredPriority through kEmergencyPriority to give some common guidelines on the magnitudes to use. The default priority level if unspecified is kStdPriority.

If you want to do some more initializations not handled by the MotionCommand's constructor (the arg1, arg2, ... params) then you would want to do something like the following:

Notice that yourmc is actually of type SharedObject, but you're calling YourMC's functions on it through the '->' operator... SharedObject is a "smart pointer" which will pass your function calls on to the underlying templated type. Isn't C++ great? :)

Definition at line 83 of file MotionManager.h.


Public Types
typedef MotionManagerMsg::MC_ID	MC_ID
	use this type when referring to the ID numbers that MotionManager hands out
Public Member Functions
	MotionManager ()
	Constructor, sets all the outputs to 0.
void	InitAccess (OSubject *subj)
	LOCKS MotionManager Everyone who is planning to use the MotionManager needs to call this before they access it or suffer a horrible fate
void	receivedMsg (const ONotifyEvent &event)
	LOCKS MotionManager This gets called by an OObject when it receives a message from one of the other OObject's MotionManagerComm Subject
void	RemoveAccess ()
	needed in order to dereference shared memory regions before shutting down
void	processMsg (RCRegion *region)
	LOCKS MotionManager This gets called by receivedMsg when under Aperios, or directly if you already have an RCRegion
	~MotionManager ()
	destructor
MotionCommand Safe
void	setOutput (const MotionCommand *caller, unsigned int output, const OutputCmd &cmd)
	LOCKS MotionManager Requests a value be set for the specified output, copies cmd across frames
void	setOutput (const MotionCommand *caller, unsigned int output, const OutputCmd &cmd, unsigned int frame)
	LOCKS MotionManager Requests a value be set for the specified output in the specified frame
void	setOutput (const MotionCommand *caller, unsigned int output, const OutputCmd cmd[NumFrames])
	LOCKS MotionManager Requests a value be set for the specified output across frames
void	setOutput (const MotionCommand *caller, unsigned int output, const OutputPID &pid)
	LOCKS MotionManager Requests a PID be set for the specified output, notice that this might be overruled by a higher priority motion
void	setOutput (const MotionCommand *caller, unsigned int output, const OutputCmd &cmd, const OutputPID &pid)
	LOCKS MotionManager Requests a value and PID be set for the specified output
void	setOutput (const MotionCommand *caller, unsigned int output, const OutputCmd cmd[NumFrames], const OutputPID &pid)
	LOCKS MotionManager Requests a value and PID be set for the specified output
const OutputCmd &	getOutputCmd (unsigned int output) const
	Returns the value of the output last sent to the OS. Note that this will differ from the sensed value in state, even when staying still. There is no corresponding getOutputPID because this value will duplicate the value in state.
void	setPriority (MC_ID mcid, float p)
	sets the priority level of a MotionCommand, symbolic values are available to give some guidelines -- see kIgnoredPriority through kEmergencyPriority
float	getPriority (MC_ID mcid) const
	returns priority level of a MotionCommand, symbolic values are available to give some guidelines -- see kIgnoredPriority through kEmergencyPriority

MC_ID	begin () const
	returns the MC_ID of the first MotionCommand
MC_ID	next (MC_ID cur) const
	returns the MC_ID of MotionCommand following the one that is passed
MC_ID	end () const
	returns the MC_ID of the one-past-the-end MotionCommand (like the STL)
unsigned int	size () const
	returns the number of MotionCommands being managed
MotionCommand "Risky"
You can have one MC check out and modify another, but make sure the other MC doesn't call setOutput()
MotionCommand *	checkoutMotion (MC_ID mcid, bool block=true)
	locks the command and possibly performs RTTI conversion; supports recursive calls
void	checkinMotion (MC_ID mcid)
	marks a MotionCommand as unused
MotionCommand *	peekMotion (MC_ID mcid)
	allows access to a MotionCommand without checking it out; warning never call a function based on this, only access member fields through it
unsigned int	checkoutLevel (MC_ID mcid)
	returns the number of times mcid has been checked out minus the times it's been checked in
bool	isOwner (MC_ID mcid)
	locks the command and possibly performs RTTI conversion; supports recursive calls
MotionCommand Unsafe
MC_ID	addPrunableMotion (const SharedObjectBase &sm, float priority=kStdPriority)
	LOCKS MotionManager adds a new motion (wrapped in a SharedObject) and marks that it should be automatically deleted when the MotionCommand::isAlive() returns false.
MC_ID	addPersistentMotion (const SharedObjectBase &sm, float priority=kStdPriority)
	LOCKS MotionManager adds a new motion (wrapped in a SharedObject) and marks that it should not be deleted, until removeMotion(MC_ID mcid) is called.
void	removeMotion (MC_ID mcid)
	LOCKS MotionManager removes the specified MotionCommand

void	lock ()
	gets an exclusive lock on MotionManager - functions marked LOCKS MotionManager will cause (and require) this to happen automatically
bool	trylock ()
	tries to get a lock without blocking
void	unlock ()
	releases a lock on the motion manager

void	getOutputs (float outputs[][NumOutputs])
	LOCKS MotionManager called by MotionObject to fill in the output values for the next NumFrames frames (only MotoObj should call this...)
void	updateWorldState ()
	call this when you want MotionManager to set the WorldState to reflect what things should be for unsensed outputs (LEDs, ears) (only MotoObj should be calling this...)
bool	updatePIDs (OPrimitiveID primIDs[NumOutputs])
	call this when you want MotionManager to update modified PID values, returns true if changes made (only MotoObj should be calling this...), see PIDMC for general PID documentation
Static Public Member Functions
static void	setTranslator (EventTranslator *et)
	sets etrans, should be called before any events can be sent
Static Public Attributes
static const unsigned int	MAX_ACCESS = 2
	This is the number of processes which will be accessing the MotionManager.
static const unsigned int	MAX_MOTIONS = 64
	This is the maximum number of Motions which can be managed, can probably be increased reasonably without trouble.
static const MC_ID	invalid_MC_ID = MotionManagerMsg::invalid_MC_ID
	for errors and undefined stuff
Priority Level Constants
Just to give you some guidelines for what values to use for different priority levels, but you can pick any value you like (that's why they are floats)
static const float	kIgnoredPriority = -1
	won't be expressed, handy if you want to temporarily pause something
static const float	kBackgroundPriority = 0
	will only be expressed if nothing else is using that joint
static const float	kLowPriority = 5
	for stuff that's not background but lower than standard
static const float	kStdPriority = 10
	for every-day commands
static const float	kHighPriority = 50
	for stuff that should override standard stuff
static const float	kEmergencyPriority = 100
	for really important stuff, such as the emergency stop
Protected Types
typedef unsigned short	accID_t
	type to use to refer to accessors of MotionManager (or its locks)
typedef ListMemBuf< OutputState, MAX_MOTIONS >	cmdstatelist_t
	shorthand for a list of OutputState's
Protected Member Functions
MC_ID	doAddMotion (const SharedObjectBase &sm, bool autoprune, float priority)
	does the actual work of adding a motion
MotionCommand *	convertMotion (MC_ID mc)
	sets up a motion command to be accessed by the current process
void	setPID (unsigned int j, const float p[3])
	LOCKS MotionManager, called internally to do the work of setting the PID... you probably want to call setOutput with an OutputPID argument, not this...
void	func_begin ()
	called at the begining of many functions to lock MotionManager
void	func_end ()
	called at the end of a function which called func_begin() to release it
template<class T>
T	func_end (T val)
	same as func_end(), except passes return value through
MC_ID	skip_ahead (MC_ID mcid) const
	during iteration, skips over motioncommands which are still in transit from on OObject to another
MC_ID	pop_free ()
	pulls an entry from cmdlist's free section and returns its index
void	push_free (MC_ID a)
	puts an entry back into cmdlist's free section
Static Protected Member Functions
static int	getAccID ()
Protected Attributes
ListMemBuf< PIDUpdate, NumPIDJoints >	pidchanges
	stores PID updates, up to one per joint (if same is set more than once, it's just overwrites previous update)
ListMemBuf< CommandEntry, MAX_MOTIONS, MC_ID >	cmdlist
	the list where MotionCommands are stored, remember, we're in a shared memory region with different base addresses - no pointers!
MC_ID	cur_cmd
	MC_ID of the MotionCommand currently being updated by getOutputs(), or NULL if not in getOutputs. This is used by the setOutput()'s to tell which MotionCommand is calling.
MutexLock< MAX_ACCESS >	MMlock
	The main lock for the class.
cmdstatelist_t	cmdstates [NumOutputs]
	requested positions by each of the MC's for each of the outputs
float	cmdSums [NumOutputs]
	Holds the final values for the outputs of the last frame generated.
OutputCmd	cmds [NumOutputs]
	Holds the weighted values and total weight for the outputs of the last frame.
accID_t	numAcc
	The number of accessors who have registered with InitAccess().
OSubject *	subjs [MAX_ACCESS]
	The OSubject for each process (accessor) on which it should be broadcast when a command is added.
Static Protected Attributes
static int	_MMaccID [ProcessID::NumProcesses]
	Stores the accessor id assigned in InitAccess() for each process.
static EventTranslator *	etrans = NULL
	EventTranslator for sending events to Main -- each process will set the correct value for calls within that process.
Private Member Functions
	MotionManager (const MotionManager &)
	this shouldn't be called...
MotionManager &	operator= (const MotionManager &)
	this shouldn't be called...
Classes
struct	CommandEntry
	All the information we need to maintain about a MotionCommand. More...
class	OutputState
	holds the full requested value of an output More...
struct	PIDUpdate
	used to request pids for a given joint More...

Member Function Documentation

MotionManager::MC_ID MotionManager::doAddMotion	(	const SharedObjectBase &	sm,
		bool	autoprune,
		float	priority
	)			`[protected]`

does the actual work of adding a motion

We have made this function protected because it's more readable if you call addPrunableMotion() or addPersistentMotion() instead... we decided requiring people to pass a true/false arguement wouldn't make it clear what that true/false was controlling.

Definition at line 767 of file MotionManager.cc.

Referenced by addPersistentMotion(), and addPrunableMotion().

void MotionManager::getOutputs ( float outputs[][NumOutputs] )

LOCKS MotionManager called by MotionObject to fill in the output values for the next NumFrames frames (only MotoObj should call this...)

What's worse? A plethora of functions which are only called, and only useful at one place, or a big massive function which doesn't pollute the namespace? This is the latter, for better or worse.

Definition at line 296 of file MotionManager.cc.

void MotionManager::setPID	(	unsigned int	joint,
		const float	pids[3]
	)			`[protected]`

LOCKS MotionManager, called internally to do the work of setting the PID... you probably want to call setOutput with an OutputPID argument, not this...

Note that we don't actually set the PIDs in the system here, we just queue them up. PID changes seem to be an expensive operation, so may only want to clear the queue at some reduced rate (although that's not actually currently being done, it just could be)

Definition at line 970 of file MotionManager.cc.

Referenced by getOutputs(), and setOutput().

bool MotionManager::updatePIDs ( OPrimitiveID primIDs[NumOutputs] )

call this when you want MotionManager to update modified PID values, returns true if changes made (only MotoObj should be calling this...), see PIDMC for general PID documentation

This function handles the conversion from the Tekkotsu format (one regular IEEE float per parameter, to the OPEN-R format (which takes a specialized, reduced precision floating point number) This is all documented in PIDMC as well.

In order to send Tekkotsu's PIDs to the system, they are converted to the gain/shift format. On the ERS-2xx, we could dynamically choose shift values to allow more precision in setting values.

With the ERS-7, all shifts are shared, so they must be set to a common set of values, defined by WorldState::DefaultPIDShifts. This limits the range of gains which can then be set.

Due to the mysterious warning which would occur with the 2xx, (AGRMSDriver::SetGain() : 0x0A IS USED FOR GAIN SHIFT VALUE.) and since this seems to be the way things are going, all models now, by default, use global shift values (which can vary from model to model, just global for each model)

You can revert to the dynamic shift selection by commenting-in the noted code section below.

A final note: the OPENR::SetJointGain function seems to be a rather costly function call. You should probably try to avoid setting PIDs at too high a frequency.

Definition at line 571 of file MotionManager.cc.

Member Data Documentation

const unsigned int MotionManager::MAX_ACCESS = 2 [static]

This is the number of processes which will be accessing the MotionManager.

Probably just MainObject and MotionObject... This isn't really a hard maximum, but should be actual expected, need to know when they're all connected

Definition at line 89 of file MotionManager.h.

Referenced by MotionManager::CommandEntry::CommandEntry(), doAddMotion(), and InitAccess().

MotionManager Class Reference

Detailed Description

Public Types

Public Member Functions

Static Public Member Functions

Static Public Attributes

Protected Types

Protected Member Functions

Static Protected Member Functions

Protected Attributes

Static Protected Attributes

Private Member Functions

Classes

Member Function Documentation

Member Data Documentation