GitHub - nxp-archive/openil_nxp-servo

nxp-servo

nxp-servo Introduction

nxp-servo is a CiA402 (also referred to as DS402) profile framework based on Igh CoE interface( An EtherCAT Master stack, see EtherCAT section for details ), and it abstracts the CiA 402 profile and provides a easy-used API for App developer.

the nxp-servo project consists of a basic library libnservo and several auxiliary tools.

The application developed with libnservo is flexible enough to adapt to the changing of CoE network by modifying the xml config file which is loaded when the application starts. The xml config file describes the necessary information, including EtherCAT network topology, slaves configurations, masters configurations and all axles definitions.

CoE Network

A typical CoE network is shown as figure below:

There are three CoE servo on this network and we name them slave x as the position they are. Each CoE servo could have more then one axle. The libnservo will initiate the CoE network and encapsulate the detail of network topology into axle nodes. So the developer could focus on the each axle operation without taking care of the network topology.

libnservo Architecture

nxp-servo is running on top of Igh EtherCAT stack. And the Igh stack provides CoE communication mechanisms - Mailbox and Process Data. Using these mechanisms, nxp-servo could access the CiA Object Dictionary located on CoE servo.

Control task initiates the master, all slaves on the CoE network and registers all PDOs to Igh stack, then constructs a data structure to describe each axle. Finally , the control task creates a task to run the user task periodically.

XML Config

This section focuses on how the xml config file describes a CoE network.

the skeleton of XML config is shown as in figure below:

<?xml version="1.0" encoding="utf-8"?>
<Config  Version="1.2">
	<PeriodTime>#10000000</PeriodTime>
	<MaxSafeStack>#8192</MaxSafeStack>
	<master_status_update_freq>#1</master_status_update_freq>
	<slave_status_update_freq>#1</slave_status_update_freq>
	<axle_status_update_freq>#1</axle_status_update_freq>
	<sync_ref_update_freq>#2</sync_ref_update_freq>
	<is_xenomai>#1</is_xenomai>
	<sched_priority>#82</sched_priority>
	<Masters>
		<Master>
			...
		<\Master>
		<Master>
			...
		<\Master>
    <\Master>
	
	<Axles>
    	<Axle>
    		...
    	<\Axle>
    	<Axle>
    		...
    	<\Axle>
    <\Axles>	
</Config>

All config elements must be inside the element.
All config elements shown above are mandatory.
The numerical value started with # means that it is a decimal value.
The numerical value started with #x means that it is a hexadecimal value.
<PeriodTime> element means that the period of control task is 10ms.
<MaxSafeStack> means the stack size, and it is an estimated value. 8K is enough to satisfy most application.
<master_status_update_freq> element means the frequency of masters status update. the value #1 means update the masters status every task period.
<slave_status_update_freq> element means the frequency of slaves status update. the value #1 means update the slaves status every task period. * <axle_status_update_freq> element means the frequency of axles status update. the value #1means update the axles status every task period.
<sync_ref_update_freq> element means the frequency of reference clock update. the value #2means update the axles status every two task period.
<is_xenomai> element means whether Xenomai is supported. the value #1 means that Xenomai is supported on this host, and #0 means not.
<sched_priority> element means the priority of the user task.
<Masters> element could contain more then one Master element . For most cases, there is only one master on a host.
<Axles> element could contain more then one Axle element, which is the developer really care about.

Master Element

As CoE network section shown, the Master could has many slaves, so the Master element will consist of some Slave elements.

	<Master>
			<Master_index>#0</Master_index>
			<Reference_clock>#0</Reference_clock>
			<Slave  alias="#0" slave_position="#0">	
            ....
            </Slave>
            <Slave  alias="#1" slave_position="#1">	
            ....
            </Slave>
     </Master>

<Master_index> element means the index of the master. as mentioned above, for many cases, there is only one master, so the value of this element is always #0.
<Reference_clock> element is used to indicate which slave will be used the reference clock.
<Slave> element means there is a slave on this master.

Slave Element

<Slave  alias="#0" slave_position="#0">				
			<VendorId>#x66668888</VendorId>
			<ProductCode>#x20181302</ProductCode>
			<Name>2HSS458-EC</Name>
			<Emerg_size>#x08</Emerg_size>
			<WatchDog>
				<Divider>#x0</Divider>
				<Intervals>#4000</Intervals>
			</WatchDog>	
			<DC> 
				<SYNC SubIndex='#0'> 
					<Shift>#0</Shift>
				</SYNC>
			</DC>		
			<SyncManagers force_pdo_assign="#1">
				<SyncManager SubIndex="#0">
					...
				</SyncManager>
		
				<SyncManager SubIndex="#1">
                    ...
				</SyncManager>
			</SyncManagers>
			<Sdos>
				<Sdo>
					...
				</Sdo>
				<Sdo>
					...
				</Sdo>
			</Sdos>					
		</Slave>

alias attribute means the alias name of this slave.
slave_position attribute means which position of the slave is on this network.
<Name> element is the name of the slave.
<Emerg_size> element is always 8 for all CoE device.
<WatchDog>element is used to set the watch dog of this slave.
<DC> element is used to set the sync info.
<SyncManagers> element should contain all syncManager channels.
<Sdos> element contains the default value we want to initiate by SDO channel.

SyncManagers Element

For a CoE device, there are generally four syncManager channels.

SM0: Mailbox output
SM1: Mailbox input
SM2: Process data outputs
SM3: process data inputs

	<SyncManager SubIndex="#0">
		<Index>#x1c10</Index>
		<Name>Sync Manager 0 </Name>
		<Dir>OUTPUT</Dir>
		<Watchdog>DISABLE</Watchdog>
		<PdoNum>#0</PdoNum>
	</SyncManager>

	<SyncManager SubIndex="#1">
		<Index>#x1c11</Index>
		<Name>Sync Manager 1</Name>
		<Dir>INPUT</Dir>
		<Watchdog>DISABLE</Watchdog>
		<PdoNum>#0</PdoNum>
	</SyncManager>

	<SyncManager SubIndex="#2">
		<Index>#x1c12</Index>
		<Name>Sync Manager 2</Name>
		<Dir>OUTPUT</Dir>
		<Watchdog>ENABLE</Watchdog>
		<PdoNum>#1</PdoNum>
		<Pdo SubIndex="#1">
			<Index>#x1600</Index>
			<Name>RxPdo 1</Name>							
			<Entry SubIndex="#1">
				...
			</Entry>
			<Entry SubIndex="#2">
				...
			</Entry>
		</Pdo>
	</SyncManager>

    <SyncManager SubIndex="#3">
		<Index>#x1c13</Index>
		<Name>Sync Manager 3</Name>
		<Dir>INPUT</Dir>
		<Watchdog>DISABLE</Watchdog>
		<PdoNum>#1</PdoNum>
		<Pdo SubIndex="#1">
			<Index>#x1a00</Index>
			<Name>TxPdo 1</Name>
			<Entry SubIndex="#1">
				...
			</Entry>
			<Entry SubIndex="#2">
				...
			</Entry>
										
		</Pdo>
	</SyncManager>

<Index> element is the object address.
<Name> is a name of this syncmanager channel.
<Dir> element is the direction of this syncmanager channel.
<Watchdog> is used to set watchdog of this syncmanager channel.
<PdoNum> element means how many PDO we want to set.
<Pdo SubIndex="#1> element contains the object dictionary entry we want to mapped.
- <Index>PDO address.
- <Name>PDO name
- <Entry> the object dictionary we want to mapped.

Entry Element

The Entry element is used to describe a object dictionary we want to mapped.

	<Entry SubIndex="#1">
		<Index>#x6041</Index>
		<SubIndex>#x0</SubIndex>
		<DataType>UINT</DataType>
		<BitLen>#16</BitLen>
		<Name>statusword</Name>
	</Entry>

Sdo Element

The Sdo element is used to set the default value of a object dictionary.

	<Sdo>	
		<Index>#x6085</Index>
		<Subindex>#x0</Subindex>
		<value>#x1000</value>
		<BitLen>#32</BitLen>
		<DataType>DINT</DataType>
		<Name>Quick_stop_deceleration</Name>
	</Sdo>

The element shown in figure above means set the object dictionary "6085" to 0x1000.

Axle Element

	<Axle master_index='#0' slave_position="#0" AxleIndex="#0" AxleOffset="#0">
			<Mode>pp</Mode>
			<Name>x-axle</Name>
			<reg_pdo>
				...
			</reg_pdo>
			<reg_pdo>
				...
			</reg_pdo>
	</Axle>

master_index attribute indicates which master this axle belong to.
slave_position attribute indicates which slave this axle belong to.
AxleOffset attribute indicates which axle this axle is on the slave. As mentioned above, a CoE slave could have more then on axle. If this axle is the second axle on the slave, set AxleOffset="#1".
<Mode> means which mode this axle will work on.
<Name> is the name of this axle.
<reg_pdo> is the PDO entry we want to register.

reg_pdo element

	<reg_pdo>	
		<Index>#x606c</Index>
		<Subindex>#x0</Subindex>
		<Name></Name>
	</reg_pdo>

Test

Hardware preparation

A CoE servo system

A CoE servo system includes a CoE servo and a motor. In this test, '2HSS458-EC' servo system shown as in figure below will be used.
A board supported on OpenIL

In this test, LS1046ARDB will be used.

Software preparation

Make sure the below config options is selected when configuring OpenIL.

BR2_PACKAGE_IGH_ETHERCAT=y
BR2_PACKAGE_LIBXML2=y
BR2_PACKAGE_NXP-SERVO=y

CoE network Detection

Igh configuration
- Configure the MASTER0_DEVICE field of the /etc/ethercat.conf
  
  Set MASTER0_DEVICE to the MAC address to indicate which port the Igh uses .
- Configure DEVICE_MODULES="generic" of the /etc/ethercat.conf
using the command ethercatctl start to start Igh service.

Check CoE servo using below command.

[root@OpenIL:~]#ethercat slaves
0  0:0  PREOP  +  2HSS458-EC

Start test

Note: The Position encoder resolution and Velocity encoder resolution of "2HSS458-EC" servo system are both 4000 . It means the ratio of encoder increments per motor revolution.

Profile Position mode test

Start the test service as below.

[root@OpenIL:~]# nservo_run -f /root/nservo_example/hss248_ec_config_pp.xml &

Check whether the status of the slave has been transferred from "PREOP" to "OP".
```
[root@OpenIL:~]# ethercat slaves
0  0:0  OP  +  2HSS458-EC
```
Check whether the phase of the master has been transferred from "Idle" to "Operation".
```
[root@OpenIL:~]# ethercat master | grep Phase 
  Phase: Operation
```

Run below commands to test whether the motor works.

Get current mode of axle 0.

[root@OpenIL:~]# nservo_client -a 0 -c get_mode 
get_mode of the axle 0 : Profile Position Mode

Get current position of axle 0.

[root@OpenIL:~]# nservo_client -a 0 -c get_position 
get_current_position of the axle 0 : 0

Get the profile speed of axle 0.

[root@OpenIL:~]# nservo_client -a 0  -c get_profile_speed
get_profile_speed of the axle 0 : 800000

The value 800000 means 200 revolutions per second.

Set profile speed of axle 0.

[root@OpenIL:~]# nservo_client -a 0  -c set_profile_speed:20000   
set_profile_speed of the axle 0 : 20000

Set profile speed to 5 revolutions per second.

Set target position of axle 0
```
[root@OpenIL:~]# nservo_client -c set_position:400000
set_position of the axle 0 : 400000
```
The value 400000 means that the motor will turn 100 rounds.

(target_position:400000 - current_position:0) / 4000 = 100

Get current speed of axle 0

[root@OpenIL:~]# nservo_client -a 0  -c get_speed
get_speed of the axle 0 : 19999

Get target position of axle 0

[root@OpenIL:~]# nservo_client -a 0  -c get_target_position
get_target_position of the axle 0 : 400000

Exit test

[root@OpenIL:~]# nservo_client  -c exit

Profile Velocity mode test

Start the test service as below.

[root@OpenIL:~]# nservo_run -f /root/nservo_example/hss248_ec_config_pv.xml &

Check whether the status of the slave has been transferred from "PREOP" to "OP".
```
[root@OpenIL:~]# ethercat slaves
0  0:0  OP  +  2HSS458-EC
```
Check whether the phase of the master has been transferred from "Idle" to "Operation".
```
[root@OpenIL:~]# ethercat master | grep Phase 
  Phase: Operation
```

Run below commands to test whether the motor works.

Get current mode of axle 0.

[root@OpenIL:~]# nservo_client -a 0  -c get_mode    
get_mode of the axle 0 : Profile Velocity Mode

Set target speed of axle 0

[root@OpenIL:~]# nservo_client -a 0  -c set_speed:40000                          set_speed of the axle 0 : 40000

The value 40000 means that the motor will turn with 10 revolutions per second.

Get current speed of axle 0

[root@OpenIL:~]# nservo_client -a 0  -c get_speed      
get_speed of the axle 0 : 32000

Get target speed of axle 0

[root@OpenIL:~]# nservo_client -a 0  -c get_target_speed                     
get_target_speed of the axle 0 : 40000

Exit test

[root@OpenIL:~]# nservo_client  -c exit

Name		Name	Last commit message	Last commit date
Latest commit History 2 Commits
_images		_images
example		example
include		include
tool		tool
LICENSE		LICENSE
Makefile		Makefile
ds402.c		ds402.c
nser_xml_parse.c		nser_xml_parse.c
nservo.c		nservo.c
nservo_config.c		nservo_config.c
readme.md		readme.md

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Repository files navigation

nxp-servo

nxp-servo Introduction

CoE Network

libnservo Architecture

XML Config

Master Element

Slave Element

SyncManagers Element

Entry Element

Sdo Element

Axle Element

reg_pdo element

Test

Hardware preparation

Software preparation

CoE network Detection

Start test

About

Releases

Packages

Languages

License

nxp-archive/openil_nxp-servo

Folders and files

Latest commit

History

Repository files navigation

nxp-servo

nxp-servo Introduction

CoE Network

libnservo Architecture

XML Config

Master Element

Slave Element

SyncManagers Element

Entry Element

Sdo Element

Axle Element

reg_pdo element

Test

Hardware preparation

Software preparation

CoE network Detection

Start test

About

Resources

License

Stars

Watchers

Forks

Releases

Packages 0

Languages

Packages