SEMBRA SEnsoristica Multi Bus per Robotica spaziale (Multibus Wired and Wireless On-Board Sensors and Actuators Networks)

Transcription

1 SEMBRA SEnsoristica Multi Bus per Robotica spaziale (Multibus Wired and Wireless On-Board Sensors and Actuators Networks) un progetto nell ambito del I Bando PMI Materiali, componenti, sensori Kayser Italia S.r.l. Via di Popogna Livorno (Italy) kayser@kayser.it

2 Company profile Kayser Italia area of business is the study, design, manufacturing, integration, testing and commissioning of systems and subsystems for space applications. The company has extensive expertise in the design and manufacturing of experiments and payloads, related GSE and Mission Operations and Support for ASI and ESA, both as prime-contractor and as sub-contractor. Today, the Company has a record of participation to 59 space missions with 87 payloads, ranging from sounding rockets, to unmanned and manned European, Russian, Japanese, Chinese platforms, to Shuttle, and ISS. 2

3 Company profile Specific expertise in: Payloads and experiments in µ-gravity Avionics Equipment Interfaces to platforms Thermal control Power conversion and distribution Ground Support Equipment (GSE) Missions and Operations Main application domains: Exploration Life sciences Physical sciences Space technologies 3

4 SEMBRA: project summary Subject: definition of a new communication bus standard for networks of low data-rate sensors and actuators, with layouts spanning over tens to one-hundred meters. Benefits: cabling simplification and mass and volume harness reduction; better ground testability of flight system, with great economical advantages in terms of mission cost savings. Applications: Space robotics Telecom satellites All space platforms and applications requiring large amount of sensors/actuators Timeline: project duration 21 months, completed 4

5 SEMBRA: background Typical requirement is the access to distributed heterogeneous sensors/actuators (S/A), with : Data-rate: up to 100kbps Number of nodes: up to 100 Latency time: < 100 msec SENSOR/ ACTUATOR SENSOR/ ACTUATOR SENSOR/ ACTUATOR OBC CANBus MIL-STD-1553B RTU CUSTOM Busses SENSOR/ ACTUATOR SENSOR/ ACTUATOR SENSOR/ ACTUATOR To implement this requirement, a Remote Terminal Unit (RTU) is typically used, consisting of a data bridge between the On Board Computer (OBC, through a Tier1 Bus like CAN Bus or MIL-STD- 1553B) and the S/A, connected via different dedicated Buses, cabled with individual connections to the RTU, typically in a star configuration 5

6 SEMBRA: project drivers Increasing interest for the adoption of a standard Bus for a class of simple S/A, with low data-rate, like temperature, pressure, current sensors, and actuators (power switches, RF, ) Main reasons : Simplify the cabling (a single bus for many S/A) Simply the location of S/A simplify design, assembly and integration Reduction of launch mass and volume Reduction of buses electrical power consumption Easier testability on ground 6

7 SEMBRA: activities performed Analysis of requirements Study and definition of interfaces between S/A Node and RTU: Wired: review of existing buses (e.g. 1-Wire, I2C, SMBus, LIN, SPI, Sensor Path) and trade-off analysis Wireless: review of existing buses (e.g. Wi-Fi, Zigbee, Bluetooth, Bluetooth Low Energy) and trade-off analysis System architecture definition System specification Design of RTU, S/A Nodes, software RTU multi-bus Manufacturing, Assembly, Integration S/A Node multi-bus Manufacturing, Assembly, Integration Command and control software development (EGSE) Functional test of each prototype and software Integration of RTU and S/A in a network representative of the selected application Test campaign 7

8 SEMBRA: system concept Acquisition system based on a twofold communication Bus : Serial Wired Bus, based on I 2 C standard (WSB) Wireless Bus, based on Bluetooth Low Energy (WLSB) Acquisition system items: Remote Terminal Unit (RTU) connecting to the OBC via CANBus and/or MIL-STD-1553B Low data-rate sensors and actuators network (S/A Nodes) 8

9 SEMBRA architecture additional benefits In flight use of the wireless bus as back-up in case of failure of the wired bus OBC On ground, during integration phases, possibility to use wireless bus as back door to emulate data acquired by the RTU via the wired bus, testing the system without altering the system software nor the system configuration. CAN / MIL-1553 EGSE CanBus interface Card WSB SEM-RTU WLSB WLSB WSB WSB WSB WSB SensorNode#1 SensorNode#2 SensorNode#3 SensorNode#N 9

10 SEMBRA: Remote Terminal Unit OBC/ EGSE CAN Bus Interface RTU prototype External SRAM External EEPROM Control Unit (CU) WLSB Interface WSB Interface WLSB Sensor Nodes Network WSB Sensor Nodes Network Local Devices 1.5V 3.3V 5V Protections 3.3V, 5V CompactPCI/External Main Power Supply 10

11 SEMBRA: integrated system 11

12 SEMBRA hypothesis of application scenario 1 - Herschel: real case: 299 sensors are distributed in the whole satellite; each sensor is connected to the acquisition board via a dedicated wire (200 thermistors) The total length for the wiring of all sensors is around 1.8Km (measured) The above results in about 300Keuro and 16 Kg for the wiring with SEMBRA: 30m wiring, for about 3Keuro and a mass of 2Kg 12

13 SEMBRA hypothesis of application scenario 2 - Exomars heat shield instrumentation discarded for mass problems: 113 Sensors (mostly thermocouples) The estimated average length for each connection is then 6m, for a total length of 678m and a total mass of about 9kg with SEMBRA: The wiring mass could be reduced to 600g and the total length to 30m. The cost is again reduced of about 95%, taking into account only harness savings! 13

14 Conclusion Project status: successfully completed Actual TRL : 4 THAG domain: OBCD (On Board Computer and Data Systems) Application domains: robotics, telecommunications, earth observation, exploration and universe observation, navigation, launchers and space transportation 14