JP2011103606A - Communication control device and communication control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique where an overhead due to a guard period between slots of a communication frame is reduced, and a transmission efficiency is enhanced, even in a communication node which can not perform transmission processing and reception processing concurrently. <P>SOLUTION: With a communication frame having a predetermined frame period as a unit, a communication control device making slot allotment to a plurality of nodes communicating by a TDMA communication system has: a generation means generating a plurality of slot groups tightly arranging one or more slots of the same transmission source node; a determining means determining the order of arranging a plurality of slot groups in the communication frame so that the number of combinations in which a transmission destination node of an end slot of preceding slot groups among adjacent two slot groups matches with a transmission source node of a head slot of subsequent slot groups becomes the minimum when the generated slot groups are arranged in chronological order; and an arranging means arranging a plurality of slot groups in the communication frame according to the determined order and inserting a guard period between the slot groups arranged. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a communication apparatus and a network system that perform communication using a TDMA communication method.

  A time division multiple (TDMA) communication system is known as an effective communication system when communicating between a plurality of nodes connected by a single transmission line. The TDMA communication method is a communication method in which a transmission time is assigned to each node in advance, and each node transmits data at the time assigned to itself. The period in which the allocation is completed is called a frame, and the allocated time interval is called a slot.

  The TDMA communication system has an advantage that there is no collision of transmission data and a delay time is guaranteed. However, on the other hand, this method needs to insert a transmission prohibition period (guard period) every time the transmission node changes. The guard period is a period necessary for preventing data from interfering with each other due to signal propagation delay in the transmission path. In general, the length of the guard period is determined based on the propagation delay time between the two farthest nodes.

  Since no node can transmit data in the guard period, transmission efficiency decreases as the guard period increases. Therefore, Patent Document 1 proposes a technique for reducing the frequency of transmission node changes by assigning slots so that transmission slots of the same node are continuous, and reducing the total guard period length per frame. Yes.

  The TDMA communication system can employ a bus topology in addition to guaranteeing a delay time. Therefore, since it is possible to reduce the wiring compared to the conventional method of individually wiring in a star shape from the central control device, it has recently been used in industrial robot control. In general, an industrial robot is controlled such that a communication node is arranged at each joint of an arm having a large number of joints, and the entire arm performs a cooperative operation while communicating between the central control unit and the node.

  Further, as disclosed in Patent Document 2, switching between whether to perform a fast Fourier transform (FFT) operation or an inverse fast Fourier transform (IFFT) operation on one module in an orthogonal frequency division multiplexing (OFDM) modulation / demodulation circuit When using it. At this time, the IFFT operation of the data to be transmitted cannot be started while the FFT operation of the received data is being executed.

  In such a situation, if slot allocation is performed considering only that the transmission slots of the same node are continuous, a location where the reception slot and the transmission slot of the same node are arranged is generated. For this reason, when using a communication node that processes a part of transmission processing and reception processing with common hardware, in addition to the delay time in the transmission path, the time required for switching from reception to transmission processing in the communication node is set. It was necessary to insert a long guard period added.

JP 2001-320394 A JP 2007-088779 A

  As described above, in a network including a communication node having a structure in which a part of the transmission process and the reception process cannot be processed in parallel because it is processed by common hardware, an overhead due to a guard period between slots of the communication frame is generated and transmitted. There was a problem that efficiency decreased.

  In view of the above problems, an object of the present invention is to provide a technique for reducing overhead due to a guard period between slots of a communication frame and increasing transmission efficiency.

  In order to solve the above-described problem, a communication control apparatus that assigns slots to a plurality of nodes that perform communication by the TDMA communication method in units of communication frames having a predetermined frame period is provided with one or more slots of the same transmission source node. And generating means for generating a plurality of slot groups arranged in such a way that there is no gap, and the end of the preceding slot group of two adjacent slot groups when the generated slot groups are arranged in time series Determining means for determining an order in which the plurality of slot groups are arranged in the communication frame so that the number of combinations in which the transmission destination node of the slot matches the transmission source node of the first slot of the subsequent slot group is minimized; The plurality of slot groups are arranged in the communication frame according to the determined order, and a gap is arranged between the arranged slot groups. Characterized in that it comprises a positioning means for inserting the de period.

  It is possible to reduce overhead due to a guard period between slots of a communication frame and increase transmission efficiency.

It is a figure which shows the structure of the system of Embodiment 1. FIG. It is a figure which shows the internal structure of the parent node of Embodiment 1, and a child node. It is a figure which shows the structure of a communication part. It is a figure which shows slot allocation of Embodiment 1. FIG. It is a figure explaining the process of the slot group production | generation part of Embodiment 1. FIG. It is a figure which shows the flow of a process of a slot group arrangement | positioning part. It is a figure explaining the process of the guard period insertion part of Embodiment 1. FIG. It is a figure explaining the process of the guard period insertion part of Embodiment 2. FIG. It is a figure which shows the slot allocation of Embodiment 2. FIG. FIG. 10 is a diagram for explaining processing of a slot group generation unit according to the second embodiment. It is a figure which shows the internal structure of the parent node of Embodiment 3. It is a figure which shows the slot allocation of Embodiment 3. It is a figure which shows the internal structure of the parent node of Embodiment 4. It is a figure which shows the slot allocation of Embodiment 4. FIG. 10 is a diagram illustrating processing of a shared slot arrangement unit according to the fourth embodiment. FIG. 10 is a diagram illustrating a system configuration of a fourth embodiment.

<Embodiment 1>
FIG. 1 is a diagram illustrating a system configuration for performing communication control of the robot arm control system according to the first embodiment.

  As shown in the figure, a parent node 100 and one or more child nodes 1 to 3 are connected by a network via a network, and the robot arm 101 is controlled via this network.

  The arm 101 has three joints, and each joint is controlled by the child nodes 1 to 3 based on an instruction from the parent node 100. As shown in the figure, the child nodes 1 to 3 are connected to motors 111 to 113, angle sensors 121 to 123, and force sensors 131 to 133 of the joints, respectively.

  For example, the child node 1 controls the elbow joint of the arm, the child node 2 controls the wrist joint, and the child node 3 controls the finger joint. The motors 111 to 113 supply power for bending each joint.

  Further, the angle sensors 121 to 123 detect the bending angle of each joint. The force sensors 131 to 133 detect force and torque applied to each joint. The force sensor 133 of the finger joint part also includes a sensor that detects the pressure applied to the fingertip, but here, it is collectively expressed as the force sensor 133.

  The parent node 100 transmits motor control information to the child node 1 for controlling the elbow joint. The motor control information includes a voltage value applied to the motor 111, for example. The child node 1 receives the motor control information from the parent node 100, and operates the motor 111 based on the control information. Further, the child node 1 acquires the current bending angle of the joint from the angle sensor 121 and transmits the acquired angle to the parent node 100 as angle information. Based on the angle information received from the child node 1, the parent node 100 generates the next control information for the motor. Communication and control similar to those between the parent node 100 and the child node 1 described above are performed between the parent node 100 and the child nodes 2 and 3, that is, wrist joint control and finger joint control.

  The parent node 100 and the child nodes 1 to 3 perform feedback control of each joint of the arm by repeating the above communication.

  The child nodes 1 to 3 transmit and receive force information between the child nodes in parallel with the communication with the parent node 100. The child node 1 transmits the force information acquired from the force sensor 131 of its own node to the child node 2. Similarly, the child node 2 transmits the haptic information of its own node to the child node 3. Further, the child node 3 transmits the haptic information of its own node to the child node 1. Each child node performs fine adjustment of the voltage applied to the motors 111 to 113 based on the received force information. For example, a large force is applied to one joint when only the parent node 100 is controlled, but such a situation can be prevented by such communication between child nodes. That is, autonomous control is performed by communication between child nodes. Each time the child nodes 1 to 3 receive one piece of motor control information from the parent node 100, one piece of force information is transmitted to the parent node.

  Since the above communication is performed by a single bus, the TDMA communication method is used as the communication method. The transmission / reception slot allocation of each node is performed by the parent node 100, and the child nodes 1 to 3 follow this allocation. It is assumed that the slot allocation information is transmitted from the parent node 100 to the child nodes 1 to 3 in advance during the initialization process and shared.

  Note that the slot allocation information for performing necessary communication in the initialization process is preset in the timing control unit 205 of the parent node 100 and the timing control unit 215 of the child nodes 1 to 3 as initial values. And

  FIG. 2 is a diagram illustrating the internal configuration of the parent node 100 and the child node 1. The child node 2 and the child node 3 have the same configuration as the child node 1.

  The motor control information generation unit 201 generates motor control information of each child node based on operation information by a user (not shown) and angle information received from the child nodes 1 to 3 and outputs the motor control information to the communication unit 300A as transmission data. The operation information by the user includes information such as the position at which the tip of the arm is reached and the start or stop of the operation when the arm performs a predetermined repeated operation.

  The motor control unit 211 controls the motor 111 based on motor control information received from the parent node 100 and force information received from other child nodes. Data reception by the motor control unit 211 is performed via the communication unit 300B.

  The angle information generation unit 212 acquires the current bending angle of the joint from the angle sensor 121, generates angle information, and outputs the angle information to the communication unit 300B as transmission data to the parent node 100. The angle information generation unit 212 outputs one angle information every time the motor control unit 211 receives one motor control information.

  The haptic information generation unit 213 acquires force or torque magnitude applied to the joint from the force sensor 131 to generate haptic information, and outputs the haptic information to the communication unit 300B as transmission data to a predetermined child node. The haptic information generation unit 213 outputs one haptic information each time the motor control unit 211 receives one piece of motor control information.

  Data transmission / reception between the motor control information generation unit 201, the motor control unit 211, the angle information generation unit 212, and the force sense information generation unit 213 is all performed via the communication units 300A and 300B.

  The communication unit modulates and demodulates data using an orthogonal frequency division multiplexing (OFDM) modulation method, and performs transmission and reception with other nodes. All communication units 300B of the parent node 100 and the child nodes 1 to 3 have the same configuration as the communication unit 300A.

  FIG. 3 is a diagram illustrating the configuration of the communication units 300A and 300B. The transmission buffer 301 temporarily holds transmission data written from the outside. When receiving a transmission timing instruction from the timing control unit 205 or the timing control unit 215, the encoding unit 302 acquires data for one slot from the transmission buffer, encodes this, and outputs it to the FFT / IFFT unit 303.

  The FFT / IFFT unit 303 is configured to be able to perform an inverse operation by switching input and output, and can perform Fourier transform and inverse Fourier transform in the same circuit. When the transmission data is input from the encoding unit 302, the FFT / IFFT unit 303 performs inverse Fourier transform on the data and outputs the result to the transmission unit 304. In addition, when receiving data is input from the receiving unit 305, the FFT / IFFT unit 303 performs a Fourier transform on the data and outputs the result to the decoding unit 306. During the operation, the FFT / IFFT unit 303 does not accept an input.

  When the transmission data is input from the FFT / IFFT unit 303, the transmission unit 304 converts the data into an analog signal and transmits the analog signal to the transmission path.

  Receiving section 305 receives a reception timing instruction from timing control section 205 or timing control section 215, converts the signal on the transmission path received during the period of one slot into a digital signal, and outputs the digital signal to FFT / IFFT section 303.

  The decoding unit 306 decodes the data input from the FFT / IFFT unit 303 and outputs it to the reception buffer 307. The reception buffer 307 temporarily holds the reception data until it is read from the outside.

  The TDMA slot allocation information is determined by the slot group generation unit 202 of the parent node 100, the slot group arrangement unit 203 that performs communication slot allocation, and the guard period insertion unit 204, and is held in the timing control unit 205. The process of determining slot allocation information will be described later.

  The timing control unit 205 of the parent node 100 controls the transmission / reception timing of the communication unit 300A according to the slot allocation for the communication frame determined by the slot group generation unit 202, the slot group arrangement unit 203, and the guard period insertion unit 204. In addition, the timing control unit 205 broadcasts frame information including a signal for synchronizing frames, a frame length, a modulation method, and the like once per frame to all child nodes. Further, the timing control unit 205 controls the communication unit 300 so that slot allocation information is transmitted to the child nodes 1 to 3 in the initial communication.

  The timing storage unit 214 stores the slot allocation information generated by the parent node 100 and received from the parent node 100 in the initialization process.

  The timing control unit 215 of the child node 1 receives the frame information transmitted from the parent node 100, and controls the communication unit 300B so that transmission / reception is performed according to the slot allocation information held in the timing storage unit 214. .

  FIG. 4 is a diagram illustrating slot assignment determined by the slot group generation unit 202, the slot group placement unit 203, and the guard period insertion unit 204 of the parent node 100. Hereinafter, a process of determining slot allocation for communication frame generation as shown in FIG. 4 will be described. First, the slot group generation unit 202 generates a slot group in which slots of the same transmission source node are arranged in time series with no gaps among slots that need to be assigned in units of communication frames having a predetermined frame period.

  FIG. 5 is a diagram illustrating processing of the slot group generation unit 202. 5A shows a list of slots that need to be allocated to one frame, and FIG. 5B shows the contents of the slot groups generated by the slot group generation unit 202.

As shown in FIG. 5A, a list of slots that need to be assigned to one communication frame is set in advance in the slot group generation unit 202 by the user, and the slot group generation unit 202 holds this list. Alternatively, based on a transmission request from a child node, a list of slots may be generated at the parent node and held. (See Embodiment 5)
In FIG. 5A, the transmission slot of the child node 1 includes a slot for transmitting angle information to the parent node and a slot for transmitting force sense information to the child node 2. The slot group generation unit 202 generates a slot group 651 of the child node 1 by collecting these transmission slots. Similarly, the slot group generation unit 202 generates a slot group 650 of the parent node 100, a slot group 652 of the child node 2, and a slot group 653 of the child node 3. The order within the slot group when the slot group generation unit 202 generates the slot group is arbitrary. For example, the received addresses may be arranged in ascending order. As described above, the slot group generation unit 202 generates a slot group by grouping slots having the same transmission node.

  The slot group placement unit 203 divides the communication frames of the slot groups generated by the slot group generation unit 202 in accordance with the number of slot groups, and determines in which order the slots are arranged in the divided communication frames.

  FIG. 6 is a diagram showing an algorithm for determining the order in which the slot group arranging unit 203 arranges the slot groups. Hereinafter, the operation of the slot group placement unit 203 will be described according to the algorithm of FIG.

  In S101, the slot group 650 is arranged at the head of the frame. In S102, the destination node at the end of slot group 650, that is, child node 3, is stored as node X. In S103, since the slot group 651 and the slot group 652 correspond to this, it progresses to S104. In S104, the slot group 651 is selected. Here, whether the slot group 651 or the slot group 652 is selected is arbitrary, but for example, the addresses of the transmission nodes in the slot group may be in ascending order.

  In S106, the slot group 651 selected in S104 is arranged next to the slot group 650. In S107, since the slot group 652 and the slot group 653 are not arranged, the process returns to S102.

  In S102, the destination node of the last slot of the slot group 651, that is, the child node 2, is stored as the node X. Since the slot group 653 corresponds to this in S103, the process proceeds to S104. In S104 to S107, the order of arranging the slot group 653 in the next order of the slot group 651 is determined, and the process returns to S102.

  In S102 to S107, the slot group 652 is arranged next to the slot group 653, and the process ends.

  Through the above processing, the slot group placement unit 203 places the slot group 650, the slot group 651, the slot group 653, and the slot group 652 in the communication frame in this order.

  The guard period insertion unit 204 instructs the timing control unit to insert a guard period between the slots based on the slot order determined by the slot group generation unit 202 and the slot group arrangement unit 203.

  FIG. 7 is a diagram for explaining the operation of the guard period insertion unit 204. In FIG. 7A, slot 501 and slot 502 are both transmission slots of node A. When the transmission source nodes of two adjacent slots are the same as described above, the guard period insertion unit 204 does not insert a guard period between these two slots.

  In FIG. 7B, a slot 503 is a slot transmitted by the node A, and a slot 504 is a slot transmitted by the node C. When the transmission source nodes of two adjacent slots are different as described above, the guard period insertion unit 204 inserts a guard period 510 between these two slots. Here, the length of the guard period 510 is a signal propagation time between two nodes farthest in the network, and is also referred to as a first guard period.

  Below, the process which the guard period insertion part 204 performs is demonstrated.

  FIG. 4 shows the relationship between the guard period and slot allocation. Here, the communication frame includes a period 660 necessary for communication in the parent node 100 and the child nodes 1 to 3 and the remaining period 640. This period 640 may be reserved in preparation for an increase in the number of nodes, or may be deleted to shorten the frame length.

  Since the slot 600 and the slot 601 are slots transmitted by the same node, the guard period insertion unit 204 does not insert a guard period between these slots. Similarly, the guard period insertion unit 204 does not insert a guard period between other slots belonging to the same slot group.

  When attention is paid to the last slot 612 of the slot group 651 and the first slot 630 of the slot group 653, the two slots have different transmission source nodes. Therefore, the guard period insertion unit 204 is between the two slots. Inserts a guard period 510. Similarly, guard period insertion section 204 inserts guard period 510 at the boundary between slot group 650 and slot group 651 and at the boundary between slot group 652 and slot group 653.

  In this slot allocation, there is no place where the transmission destination node and the transmission source node match between adjacent slots. The communication unit 300 of the present system shares the FFT / IFFT unit 303 for transmission processing and reception processing. For this reason, when the transmission destination node and the transmission source node match between adjacent slots, a long guard period including the time for the communication unit 300 to switch from reception to transmission is necessary for the signal propagation time. With slot allocation as shown in FIG. 4, it is not necessary to take this long guard period.

  As described above, in this embodiment, the number of combinations in which the transmission destination node of the last slot of the preceding slot group and the transmission source node of the first slot of the succeeding slot group match among the adjacent two slot groups is the smallest. The slot group is arranged in the communication frame so that In the example of this embodiment, the case where the value of the number of combinations is zero has been described.

  As described above, according to the present embodiment, it is necessary to lengthen the one guard period in a network composed of communication nodes having a structure in which a part of transmission processing and reception processing is processed by common hardware. Disappear. In addition, the frequency of changing the transmission node can be reduced to reduce the number of appearances of the guard period, and overhead can be reduced.

  According to the present embodiment, since the total length of the guard periods in the period 660 can be shortened, the entire period 660 is shortened. That is, the length of the period 640 is increased.

  For example, consider replacing the motor 111 and the angle sensor 121 with higher accuracy and performing highly accurate feedback control using more detailed motor control information and angle information. In this case, it is necessary to increase the number of bits of motor information and angle information transmitted / received between the master station 100 and the slave station 1, but this is easily performed by generating a margin in the period 640 according to the present embodiment. be able to. That is, the motor control can be made highly accurate without changing the control cycle.

  Similarly, if the period 640 can be increased, the number of child nodes that control the joint can be increased without increasing the control cycle. For example, it is possible to increase the number of fingers and increase the stability when grasping an object. .

  Furthermore, by deleting the period 640, the control cycle can be shortened to perform feedback control with a higher response speed.

  Although the robot arm control system has been described as an example here, the present invention is also applicable to other systems that perform communication using the TDMA communication method.

  In the present embodiment, the parent node 100 determines slot allocation. However, it is needless to say that any one node in the network can determine the slot assignment by having the slot group generation unit 202 and the slot group arrangement unit 203.

<Embodiment 2>
The system configuration of the second embodiment is the same as that of the first embodiment shown in FIG.

  However, in this embodiment, the finger joint of the child node 3 in the arm 101 is fixed, and higher-speed control is performed using only the elbow joint and wrist joint of the child nodes 1 and 2. For this reason, communication is not performed with respect to the child node 3, and the motor 113, the angle sensor 123, and the force sensor 133 are not operated.

  The child nodes 1 and 2 control these two joints based on an instruction from the parent node 100. The child node 1 transmits the force information acquired from the force sensor 131 of its own node to the child node 2. Similarly, the child node 2 transmits the haptic information of its own node to the child node 1. The other communication contents are the same as those in the first embodiment.

  The internal configuration of the parent node 100, the child node 1, and the child node 2 is the same as that in FIG. 2 described in the first embodiment.

  Here, in the present embodiment, in order to insert a long guard period only at a location where the transmission destination (reception) node and the transmission source node of adjacent slots match, the operation of the guard period insertion unit 204 is as follows. replace.

  FIG. 8 is a diagram for explaining the operation of the guard period insertion unit 204 in the present embodiment.

  Similarly to the first embodiment, when the slots having the same transmission source node are adjacent to each other as shown in FIG. 8A, the guard period insertion unit 204 does not insert a guard period between these slots.

  On the other hand, the guard period insertion unit 204 performs processing different from that of the first embodiment when slots having different transmission source nodes are adjacent to each other as shown in FIGS. 8B and 8C. Details will be described below.

  In FIG. 8B, a slot 503 is a slot transmitted by the node A and received by the node B, and a slot 504 is a slot transmitted by the node C and received by the node D. When the transmitting node of two adjacent slots is different and the receiving node of the preceding slot 503 is different from the transmitting node of the succeeding slot 504, the guard period inserting unit 204 sets the guard period 510 between these two slots. Insert. The length of the guard period 510 is the signal propagation time between the two farthest nodes in the network.

  In FIG. 8C, the slot 505 is transmitted by the node A as the transmission source and received by the node B as the transmission destination node, and the slot 506 is transmitted by the node B as the transmission source node. This is a slot received by node C, which is a transmission destination node. When the transmission source nodes of two adjacent slots are different and the transmission destination node of the preceding slot 505 matches the transmission source node of the subsequent slot 506, the guard period insertion unit 204 A guard period 511 is inserted into The length of the guard period 511 is set to the length of the guard period 510 plus the time necessary for the communication unit 300 to switch from reception to transmission. This length is equal to the sum of the processing time in the FFT / IFFT unit 303, the processing time in the transmission unit 304, and the processing time in the reception unit 305. Here, the guard period 511 is also referred to as a second guard period.

  FIG. 9 is a diagram illustrating slot assignment determined by the slot group generation unit 202, the slot group placement unit 203, and the guard period insertion unit 204 of the parent node 100 in the second embodiment.

  Hereinafter, a process of determining slot allocation will be described in detail. FIG. 10 is a diagram illustrating processing of the slot group generation unit 202.

  FIG. 10A shows a list of slots that need to be allocated, and FIG. 10B shows the contents of the slot group generated by the slot group generation unit 202. First, the slot group generation unit 202 generates a slot group 850 of the parent node 100, a slot group 851 of the child node 1, and a slot group 852 of the child node 2 in the same procedure as in the first embodiment.

  Hereinafter, the operation of the slot group placement unit 203 will be described according to the algorithm of FIG. In S101, the slot group 850 is arranged at the head of the frame. In S102, the destination node of the end slot of slot group 850, that is, child node 2, is stored as node X. Since the slot group 851 corresponds to this in S103, the process proceeds to S104.

  In S104, the slot group 851 is selected. In S106, the selected slot group 851 is arranged next to the slot group 850. In S107, since the slot group 852 is not arranged, the process returns to S102.

  In S102, the transmission destination (reception) node of the last slot of the slot group 850, that is, the child node 2 is stored as the node X. In S103, since there is no corresponding slot group, the process proceeds to S105.

  In S106, the selected slot group 852 is placed next to the slot group 851. In S107, since there is no unallocated slot group, the process is terminated. Through the above processing, the slot group placement unit 203 places the slot group 850, the slot group 851, and the slot group 852 in the communication frame in this order.

  Next, operations related to the slot and guard period insertion unit 204 will be described with reference to FIG. Since the slot 800 and the slot 801 are slots transmitted by the same parent node, the guard period insertion unit 204 does not insert a guard period between these two slots. Similarly, the guard period insertion unit 204 does not insert a guard period between other slots belonging to the same slot group.

  The transmission destination node (child 2) in the last slot 802 of the slot group 850 and the transmission source node (child 1) in the first slot 810 of the slot group 851 do not match. Therefore, the guard period insertion unit 204 inserts a short guard period 510 between the slot group 850 and the slot group 851.

  On the other hand, the transmission destination node (child 2) in the last slot 812 of the slot group 851 matches the transmission node (child 2) in the first slot 820 of the slot group 852. Therefore, the guard period insertion unit 204 inserts a long guard period 511 between the slot group 851 and the slot group 852.

  Looking at the slot assignments in FIG. 9, in the slots 812 and 820, the transmission destination node (child 2) and the transmission source node (child 2) are continuous. Also, a guard period sufficient for switching from reception to transmission in the communication unit 300B is inserted only between these two slots.

  In addition, for example, from the transmission destination node (child 1) of the slot 801 and the transmission source node (parent) of the slot 802 to the transmission processing from reception to transmission between slots where the transmission destination (reception) node and the transmission source node do not match. The guard period corresponding to the switching time to is not inserted. That is, it can be seen that a guard period having a useless length is not inserted.

  As described above, according to the present embodiment, when the slots of the same transmission source node are arranged consecutively, a location where the transmission destination node and the transmission destination node coincide between adjacent slots always occurs. In addition, it is not necessary to insert a long guard period other than that place. Therefore, it can be seen that it is possible to increase the transmission efficiency by reducing the overhead due to the guard period.

<Embodiment 3>
The system configuration in the third embodiment is also the same as the configuration shown in FIG. FIG. 11 shows the configuration of the parent node 100 in the third embodiment. In this figure, the configuration is the same as that of the first embodiment except that a slot exchanging unit 206 is newly added to the parent node 100. Also, the internal configuration of the child nodes 1 and 2 is the same as that of the first embodiment shown in FIG. Here, only components that have not been described so far will be described.

  The slot exchanging unit 206 is added to suppress the occurrence of transmission slots and reception slots of the same node at the boundary of the slot group. Details will be described below.

  The slot group arranging unit 203 detects that the condition that the transmission destination node and the transmission source node are not matched between adjacent slots is not satisfied in the processing step S103 of FIG. Using the detection as a trigger, the arrangement order of two arbitrary slots in the slot group arranged last by the slot group arrangement unit 203 is changed. Further, after changing the slot order, the slot exchanging unit 206 instructs the slot group arranging unit 203 to redo the process from the beginning.

  The slot group placement unit 203 places the slot group 850 of the parent node 100 and the slot group 851 of the child node 1 in the same procedure as in the second embodiment. Thereafter, in process step S103 of FIG. 6, since there is no corresponding slot group, the process proceeds to S105.

  The slot exchanging unit 206 detects this, and controls the slot group arranging unit 203 to redo the process from the beginning after changing the slot order within the slot group 851 arranged last. .

  FIG. 12 is a diagram illustrating operations related to slot allocation and guard period insertion in the third embodiment. FIG. 12 shows a comparison of slot assignments when the parent node 100 has a slot group arrangement unit 203 and a slot exchange unit.

  In the second embodiment, the slot allocation determined by the slot group generation unit 202, the slot group arrangement unit 203, and the guard period insertion unit 204 is as shown in FIG.

  On the other hand, when the slot exchanging unit 206 is introduced as in the present embodiment, the slot allocation determined by the slot group generating unit 202, the slot group arranging unit 203, the guard period inserting unit 204, and the slot exchanging unit 206 is as shown in FIG. It becomes like (B).

  By changing the slot arrangement order in the slot group 851, the receiving node (transmission destination node) in the last slot 810 of the slot group 851 does not match the transmission source node in the first slot 820 of the slot group 852. Therefore, by inserting a short guard period 510 between the slot group 851 and the slot group 852, communication can be performed without any problem even if there is no long guard period 511.

  As described above, according to the present embodiment, it is possible to further reduce overhead and increase transmission efficiency by exchanging the arrangement order of slots in the same slot group.

<Embodiment 4>
The system configuration in the fourth embodiment is also the same as the configuration shown in FIG. Here, a shared slot is introduced as a new element. This shared slot is a slot for sequentially transmitting each of the nodes having different transmission sources for each communication frame. Here, consider child nodes 1 to 3 having different transmission sources. In this case, the child node 2 and the child node 3 do not transmit angle information to the parent node 100. In addition, the child nodes 1 to 3 transmit force information once every three frames. That is, force information is transmitted from child node 1 to child node 2 in the first frame, from child node 2 to child node 3 in the next frame, and from child node 3 to child node 1 in the next frame. Shall be repeated.

  FIG. 13 shows the configuration of the parent node 100 in the fourth embodiment. The internal configuration of the parent node 100 is the same as that of the first embodiment except that the shared slot arrangement unit 207 is newly added to the parent node 100. The internal configuration of the child nodes 1 to 3 is the same as that of the first embodiment except that the haptic information generation unit 213 outputs the haptic information only once every three frames as described above. .

  In this embodiment, it is assumed that the possibility that a large force is suddenly applied to some joints is small, and the purpose is to increase the response speed of motor control. As a result, the frequency of communication of force information is reduced. ing.

  The shared slot arrangement unit 207 is added for the purpose of arranging the transmission destination node and the transmission source node so as not to match between adjacent slots even when a common slot that is transmitted by different nodes depending on the communication frame is included. Is. The details will be described below.

  The shared slot arrangement unit 207 controls the slot group generation unit 202 to generate a shared slot as an independent slot group when there is a shared slot whose transmission source node changes depending on the frame. In addition, the shared slot arrangement unit 207 creates a list of nodes that have an opportunity to transmit in the shared slot group.

  Furthermore, when the slot group placement unit 203 selects a shared slot group in step S104 of FIG. 6, the shared slot placement unit 207 refers to a list of nodes that have an opportunity to transmit in the shared slot group. If the slot group placement unit 203 includes the node X set in step S102 of FIG. 6 in this list, the slot group placement unit 203 is controlled to return to S103 and search for another slot group. To do.

  FIG. 14 is a diagram illustrating slot allocation determined by the slot group generation unit 202, the slot group arrangement unit 203, the guard period insertion unit 204, and the shared slot arrangement unit 207 of the parent node 100 in the present embodiment.

  Hereinafter, a process of determining slot allocation will be described in detail.

  FIG. 15 is a diagram for explaining the operation of the shared slot arrangement unit 207. FIG. 15A shows a list of slots that need to be allocated, and FIG. 15B shows the contents of the slot groups that the shared slot placement unit 207 generates by controlling the slot group generation unit 202, respectively. . FIG. 15C shows a list of nodes that have the opportunity to transmit in the shared slot group 1252 generated by the shared slot arrangement unit 207.

  The haptic information in FIG. 15A is transmitted in the shared slot. For this reason, the shared slot arrangement unit 207 controls the slot group arrangement unit 203 to generate a shared slot for transmitting haptic information as an independent slot group. As a result, the generated slot group is as shown in FIG.

  Here, the slot group arrangement unit 203 creates a list of transmission nodes of the shared slot group 1252 in FIG. Since the haptic information is transmitted by the child nodes 1 to 3, the list of transmission source nodes of the shared slot group 1252 is as shown in FIG.

  Next, the manner in which the slot group placement unit 203 places the slot group while being controlled by the shared slot placement unit 207 will be described. The slot group arrangement unit 203 arranges the slot group 1250 at the head of the frame in S101 of FIG.

  In S102, the destination (reception) node of the last slot of the slot group 1250, that is, the child node 3 is stored as the node X. In S103, since the slot group 1251 and the shared slot group 1252 correspond to this, the process proceeds to S104.

  In the case where there are a plurality of candidates in S104, an arbitrary slot group is selected, and here, the shared slot group 1252 is selected. Here, the shared slot arranging unit 207 detects that the slot group arranging unit 203 has selected the shared slot group in S104. Furthermore, the shared slot arrangement unit 207 detects that the child node 3 stored as the node X in S102 is included in the list of FIG. Therefore, the shared slot arrangement unit 207 controls the slot group arrangement unit 203 to return to S103 and search for another slot group.

  The slot group placement unit 203 returns to S103, selects the slot group 1251 in S104, and places the slot group 1251 in the position next to the slot group 1250 in S106. In S107, since an unallocated slot group remains, the process returns to S102. In S102, the receiving node of the last slot of the slot group 1251, that is, the parent node 100 is stored as the node X.

  In S103, since the shared slot group 1252 corresponds, the process proceeds to S104. In S104, the shared slot group 1252 is selected. Here again, the shared slot arranging unit 207 detects that the slot group arranging unit 203 has selected the shared slot group in S104. Furthermore, the shared slot arrangement unit 207 detects that the parent node 100 stored as the node X in S102 is not included in the list of FIG.

  Therefore, the shared slot arrangement unit 207 controls the slot group arrangement unit 203 to proceed to S106 without returning to S103. The slot group placement unit 203 places the selected shared slot group 1252 next to the slot group 1251 in S106. In S107, since there is no unallocated slot group, the process is terminated.

  The slot assignment shown in FIG. 14 is generated by the above processing. Here, the receiving node of the slot 1210 is the parent node 100. On the other hand, child nodes 1 to 3 can be transmission nodes in the shared slot 1270. That is, the transmission destination (reception) node of slot 1210 and the transmission source node of shared slot 1270 are always different.

  Therefore, in this slot allocation, there is no place where the transmission destination node and the transmission source node match between adjacent slots. The communication unit 300 of this system shares the FFT / IFFT unit 303 in transmission processing and reception processing. For this reason, a long guard period 511 is required when reception slots and transmission slots of the same node are continuous, but a long guard period is not required if slot allocation is performed as shown in FIG.

  As described above, according to the present embodiment, it is understood that by preparing a shared slot for a slot whose transmission source node changes according to a frame, overhead due to a guard period can be reduced and transmission efficiency can be increased. .

<Embodiment 5>
The system configuration in the fifth embodiment is also the same as the configuration shown in FIG. FIG. 16 is a diagram showing an internal configuration of the parent node 100 and the child node 1. Child node 2 and child node 3 have the same configuration as child node 1.

  In FIG. 16, the difference from the first embodiment is that a slot request unit 216 is added to the parent node 100 and the child nodes 1 to 3, and the slot group generation unit 202 determines the slot based on the request from the slot request unit 216 of each node. It is a point that generates a group.

  In this case, the slot request unit 216 is provided in each child node. Even if the user does not set a list of slots that need to be allocated to the communication frame, the slot request unit 216 makes a transmission request from the child node to the parent node, thereby generating a list of slots in the parent node. Details are described below.

  In the initialization process, the slot request unit 216 of the child node 1 generates its own slot request information and transmits it to the parent node 100 via the communication unit 300. The slot request information includes a destination of data scheduled to be transmitted by the child node 1 in one frame and the number of slots corresponding to the amount of data necessary for transmitting the data.

  For example, when performing the same communication as in the first embodiment, the contents of the slot request information generated by the slot request unit 216 of the child node 1 include information such as 1 slot addressed to the parent node 100 and 1 slot addressed to the child node 2. included. Similarly, the content of the slot request information generated by the slot request unit 216 of the child node 2 includes information such as 1 slot addressed to the parent node 100 and 1 slot addressed to the child node 3. Further, the content of the slot request information generated by the slot request unit 216 of the child node 3 includes information such as 1 slot addressed to the parent node 100 and 1 slot addressed to the child node 1.

  The slot request information generated by the slot request unit 216 of the parent node 100 includes 1 slot for broadcast transmission to all child nodes, 1 slot for the child node 1, 1 slot for the child node 2, Information that one slot is addressed to the node 3 is included.

  The slot group generation unit 202 of the parent node 100 stores the slot request information received from the slot request unit 216 of each node together as a list of slots that need to be allocated to one frame as shown in FIG. To do.

  The slot group generation unit 202 starts generation of a slot group after waiting for a predetermined time in order to give the slot request unit 216 of each node time to transmit slot request information. The slot group is generated in the same procedure as described in the first embodiment, and a slot group as shown in FIG. 5B is generated.

  That is, a list of slots that need to be allocated to one frame is automatically generated between the parent node 100 and the child nodes 1 to 3 without setting by the user. For example, consider a case where the angle sensor of the child node 1 is replaced with a high-accuracy sensor. If the angle sensor is highly accurate, more precise feedback control is possible, but the data to be transmitted as angle information increases. The slot request unit 216 includes the number of transmission slots addressed to the parent node 100 in the slot request information as a sufficient number of slots for transmitting the increased data, and transmits it to the parent node 100. As a result, the slot group generation unit 202 of the parent node 100 can generate a slot group after securing a slot for increased angle information.

  Therefore, even if the user does not set a list of slots to be allocated to one frame, the fingertips having different accuracy and the number of joints can be changed and operated, so that the system can be expanded further easily.

  As described above, according to the present embodiment, even when the number of slots required for communication changes due to a change in the configuration of the network system, the change is automatically handled and the overhead due to the guard period is reduced. This can reduce the transmission efficiency.

Claims (9)

A communication control apparatus that assigns slots in units of communication frames having a predetermined frame period to a plurality of nodes that perform communication using a TDMA communication method,
Generating means for generating a plurality of slot groups in which one or more slots of the same source node are arranged without gaps;
When the plurality of generated slot groups are arranged in time series, a transmission destination node of the last slot of the preceding slot group and a transmission source node of the first slot of the following slot group among the adjacent two slot groups. Determining means for determining an order of arranging the plurality of slot groups in the communication frame so that the number of matching combinations is minimized;
A communication control apparatus comprising: a plurality of slot groups arranged in the communication frame according to the determined order; and an arrangement unit that inserts a guard period between the plurality of arranged slot groups. When the transmission destination node of the last slot of the preceding slot group and the transmission source node of the first slot of the succeeding slot group do not match among the two adjacent slot groups, the arrangement means Insert the first guard period at the boundary of
When the transmission destination node of the last slot of the preceding slot group and the transmission source node of the first slot of the succeeding slot group coincide with each other among the two adjacent slot groups, the arrangement means The communication control device according to claim 1, wherein a second guard period longer than the first guard period is inserted at a boundary of the first guard period.   By changing the arrangement order of the slots of the preceding or succeeding slot group of the two adjacent slot groups, the destination node of the last slot of the preceding slot group and the head of the succeeding slot group of the adjacent slot groups The communication control apparatus according to claim 1, further comprising switching means for minimizing a combination that matches the transmission source node of the slot.   The generating unit generates a shared slot group transmitted by a node having a different transmission source for each frame, and when the arranging unit arranges the shared slot in the communication frame, the end of the slot group preceding the shared slot is generated. 2. The shared slot is arranged in the frame so that the number of combinations that match the source node of the first slot of the shared slot group is the minimum number of combinations of the slot destination nodes. Communication control device.   The generating unit generates a shared slot group transmitted by a node having a different transmission source for each frame, and when the arranging unit arranges the shared slot in the communication frame, a head of the slot group subsequent to the shared slot is generated. 2. The shared slot is arranged in the frame so that the number of combinations in which the slot source node matches the destination node of the end slot of the shared slot group is the minimum. Communication control device.   The communication control apparatus according to claim 1, wherein the generation unit generates the plurality of slot groups based on transmission requests from one or more nodes of the plurality of nodes.   The communication control apparatus according to claim 6, wherein the transmission request includes a destination of transmission data and a number of slots corresponding to a data amount necessary for transmitting the data. A system having a plurality of nodes that communicate with each other by a TDMA communication system, and a communication control device that assigns slots to the plurality of nodes in units of communication frames having a predetermined frame period,
The communication control device includes:
Generating means for generating a plurality of slot groups in which one or more slots of the same source node are arranged without gaps;
When the plurality of generated slot groups are arranged in time series, a transmission destination node of the last slot of the preceding slot group and a transmission source node of the first slot of the following slot group among the adjacent two slot groups. Determining means for determining an order of arranging the plurality of slot groups in the communication frame so that the number of matching combinations is minimized;
Arranging means for arranging the plurality of slot groups in the communication frame according to the determined order, and inserting a guard period between the plurality of arranged slot groups;
Have
The plurality of nodes are:
A system comprising: communication means for performing communication using the communication frame in which the plurality of slot groups are arranged by the arrangement means. A communication control method for allocating slots in units of communication frames having a predetermined frame period to a plurality of nodes performing communication in a TDMA communication system,
A generating step for generating a plurality of slot groups, wherein the generating means arranges one or more slots of the same source node without gaps;
When the determining unit arranges the plurality of generated slot groups in time series, the transmission destination node of the last slot of the preceding slot group and the transmission of the first slot of the subsequent slot group among the adjacent two slot groups A determination step of determining an order of arranging the plurality of slot groups in the communication frame so that the number of combinations that match the original node is minimized;
An arrangement means comprising: an arrangement step of arranging the plurality of slot groups in the communication frame according to the determined order and inserting a guard period between the plurality of arranged slot groups. .

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