tutorial: further updates to v0.9

- update code samples
- drop logger (to be replaced with mqueues)

Signed-off-by: Markus Klotzbuecher <mk@mkio.de>

docs/user/tutorial.rst

@@ -304,8 +304,11 @@ Final listings of the block
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 The plant is, *mutatis mutandis*, built following the same rationale,
-and will be not detailed here. the final code of the plant and the
-controller can be retrieved here **TODO add link to the code**
+and will be not detailed here. The final code of the plant and the
+controller can be retrieved here:
+
+- :download:`platform_2dof.c <../../examples/platform/platform_2dof.c>`.
+- :download:`platform_2dof_control.c <../../examples/platform/platform_2dof_control.c>`.
 
 Compiling the blocks
 ~~~~~~~~~~~~~~~~~~~~
@@ -333,14 +336,16 @@ Deployment via the usc (microblx system composition) file
 independently. We want to run and compose them together and save the
 results in a logger file.  The composition file
 **platform_2dof_and_control.usc** is quite self explanatory: It
-indicates
+contains
 
-- which libraries are imported,
-- which blocks (name, type) are created,
-- the configuration values of properties.
+- the libraries to be imported,
+- which blocks (name, type) to create,
+- the configuration values of blocks.
 - the connections among ports
 
-The code is the following
+The file :download:`platform_2dof_and_control.usc
+<../../examples/platform/platform_launch/platform_2dof_and_control.usc>`
+is shown below:
 
 .. literalinclude:: ../../examples/platform/platform_launch/platform_2dof_and_control.usc
    :language: lua
@@ -431,7 +436,7 @@ Setup the build system starting from the build part
 
 *configure.am*
 
-:: code::
+.. code::
 
    m4_define([package_version_major],[0])
    m4_define([package_version_minor],[0])

examples/platform/platform_2dof.c

@@ -1,127 +1,114 @@
 #include "platform_2dof.h"
-#include "math.h"
+#include <math.h>
 
-/* define a structure for holding the block local state. By assigning an
- * instance of this struct to the block private_data pointer (see init), this
- * information becomes accessible within the hook functions.
- */
 struct robot_state {
-  double pos[2];
-  double vel[2];
-  double vel_limit[2];
+	double pos[2];
+	double vel[2];
+	double vel_limit[2];
 };
+
 double sign(double x)
 {
-  if(x > 0) return 1;
-  if(x < 0) return -1;
-  return 0;
+	if(x > 0) return 1;
+	if(x < 0) return -1;
+	return 0;
 }
 
 struct platform_2dof_info
 {
-  /* add custom block local data here */
-  struct robot_state r_state;
-  struct ubx_timespec last_time;
-  /* this is to have fast access to ports for reading and writing, without
-         * needing a hash table lookup */
-  struct platform_2dof_port_cache ports;
+	/* add custom block local data here */
+	struct robot_state r_state;
+	struct ubx_timespec last_time;
+
+	/* this is to have fast access to ports for reading
+         * and writing, without needing a hash table lookup */
+	struct platform_2dof_port_cache ports;
 };
 
 /* init */
 int platform_2dof_init(ubx_block_t *b)
 {
-  int ret = -1;
-  long len;
-  struct platform_2dof_info *inf;
-  //  double pos_vec[2];
-  double *pos_vec;
-
-  /* allocate memory for the block local state */
-  if ((inf = calloc(1, sizeof(struct platform_2dof_info)))==NULL) {
-      ubx_err(b, "platform_2dof: failed to alloc memory");
-      ret=EOUTOFMEM;
-      goto out;
-    }
-  b->private_data=inf;
-  update_port_cache(b, &inf->ports);
-
-  //read configuration - initial position
-  if ((len = ubx_config_get_data_ptr(b, "initial_position",(void **)&pos_vec)) < 0) {
-      ubx_err(b, "platform_2dof: failed to load initial_position");
-      goto out;
-    }
-  inf->r_state.pos[0]=pos_vec[0];
-  inf->r_state.pos[1]=pos_vec[1];
-  if ((len = ubx_config_get_data_ptr(b, "joint_velocity_limits",(void **)&pos_vec)) < 0) {
-      ubx_err(b, "platform_2dof: failed to load joint_velocity_limits");
-      goto out;
-    }
-  //read configuration - max velocity
-  inf->r_state.vel_limit[0]=pos_vec[0];
-  inf->r_state.vel_limit[1]=pos_vec[1];
-
-  inf->r_state.vel[0]=inf->r_state.vel[1]=0.0;
-  ret=0;
-out:
-  return ret;
-}
+	long len;
+	struct platform_2dof_info *inf;
+	const double *pos_vec;
 
-/* start */
-int platform_2dof_start(ubx_block_t *b)
-{
-  struct platform_2dof_info *inf = (struct platform_2dof_info*) b->private_data;
+	/* allocate memory for the block local state */
+	if ((inf = calloc(1, sizeof(struct platform_2dof_info)))==NULL) {
+		ubx_err(b,"platform_2dof: failed to alloc memory");
+		return EOUTOFMEM;
+	}
+
+	b->private_data=inf;
+	update_port_cache(b, &inf->ports);
+
+	/* read configuration - initial position */
+	len = cfg_getptr_double(b, "initial_position", &pos_vec);
 
-  ubx_info(b, "platform_2dof start");
-  ubx_gettime(&(inf->last_time));
+	/* this will never assert unless we made an error
+	 * (e.g. mistyped the configuration name), since min/max
+	 * checking will catch misconfigurations before we get
+	 * here. */
+	assert(len==2);
 
+	inf->r_state.pos[0] = pos_vec[0];
+	inf->r_state.pos[1] = pos_vec[1];
 
+	/* read configuration - max velocity */
+	len = cfg_getptr_double(b, "joint_velocity_limits", &pos_vec);
+	assert(len==2);
 
-  int ret = 0;
-  return ret;
+	inf->r_state.vel_limit[0] = pos_vec[0];
+	inf->r_state.vel_limit[1] = pos_vec[1];
+	inf->r_state.vel[0] = inf->r_state.vel[1] = 0.0;
+
+	return 0;
 }
 
-/* stop */
-void platform_2dof_stop(ubx_block_t *b)
+int platform_2dof_start(ubx_block_t *b)
 {
-  /* struct platform_2dof_info *inf = (struct platform_2dof_info*) b->private_data; */
- ubx_info(b, "platform_2dof stop");
-
+	struct platform_2dof_info *inf = (struct platform_2dof_info*) b->private_data;
+	ubx_info(b, "platform_2dof start");
+	ubx_gettime(&(inf->last_time));
+	return 0;
 }
 
 /* cleanup */
 void platform_2dof_cleanup(ubx_block_t *b)
 {
-  /* struct platform_2dof_info *inf = (struct platform_2dof_info*) b->private_data; */
-  ubx_info(b, "platform_2dof cleanup");
-  free(b->private_data);
+	/* struct platform_2dof_info *inf = (struct platform_2dof_info*) b->private_data; */
+        ubx_info(b, "%s", __func__);
+	free(b->private_data);
 }
 
-/* step */
 void platform_2dof_step(ubx_block_t *b)
 {
-  int32_t ret;
-  double velocity[2];
-  struct ubx_timespec current_time, difference;
-  struct platform_2dof_info *inf = (struct platform_2dof_info*) b->private_data;
-  //compute time from last call
-  ubx_gettime(&current_time);
-  ubx_ts_sub(&current_time,&(inf->last_time),&difference);
-  inf->last_time=current_time;
-  double time_passed= ubx_ts_to_double(&difference);
-
-  //read velocity from port
-  ret = read_desired_vel_2(inf->ports.desired_vel, &velocity);
-  if (ret<=0){ //nodata
-      velocity[0]=velocity[1]=0.0;
-      ubx_err(b, "no velocity data");
-    }
-
-  for (int i=0;i<2;i++){// saturate and integrate velocity
-      velocity[i]=fabs(velocity[i])> inf->r_state.vel_limit[i]? sign(velocity[i])*(inf->r_state.vel_limit[i]):velocity[i];
-      inf->r_state.pos[i]+=velocity[i]*time_passed;}
-  //write position in the port
-  write_pos_2(inf->ports.pos,&(inf->r_state.pos));
-
+	int32_t ret;
+	double velocity[2];
+	struct ubx_timespec current_time, difference;
+	struct platform_2dof_info *inf = (struct platform_2dof_info*) b->private_data;
+
+	/* compute time from last call */
+	ubx_gettime(&current_time);
+	ubx_ts_sub(&current_time,&(inf->last_time),&difference);
+	inf->last_time=current_time;
+	double time_passed = ubx_ts_to_double(&difference);
+
+	/* read velocity from port */
+	ret = read_double_array(inf->ports.desired_vel, velocity, 2);
+
+	if (ret <= 0) { /* nodata */
+		velocity[0] = velocity[1] = 0.0;
+		ubx_err(b,"no velocity data");
+	}
+
+	for (int i=0; i<2; i++) {
+		/* saturate and integrate velocity */
+		velocity[i] =
+			fabs(velocity[i]) > inf->r_state.vel_limit[i] ?
+			sign(velocity[i]) * (inf->r_state.vel_limit[i]) : velocity[i];
+
+		inf->r_state.pos[i] += velocity[i] * time_passed;
+	}
+	/* write position in the port */
+	write_double_array(inf->ports.pos, inf->r_state.pos, 2);
 }
-
-

examples/platform/platform_2dof.lua

@@ -15,5 +15,5 @@ return block
       { name="desired_vel", in_type_name="double", in_data_len=2, doc="desired velocity [m/s]" }
    },
 
-   operations = { start=true, stop=true, step=true }
+   operations = { start=true, step=true }
 }