# Recovery Motion Analysis for False Ceiling Inspection Robot
## 1 Introduction  
False ceilings are often used in buildings to store and hide disorderly but essential building infrastructure [1, 2] such as heating, ventilation ducts and air-conditioning (HVAC), electrical wiring, and plumbing systems [3]. The false ceiling space, also known as the plenum, acts as an infrastructural measure to limit fire damage [4] and regulate the thermal conditions [5] and acoustical capabilities [6, 7] of the main space below. Maintenance works on false ceilings have to be conducted on a regular basis. Otherwise, there would be potential health and safety compromises to building occupants because of pest infestations and other forms of degradation in false ceilings [8]. Infrastructural elements could be tampered with by pests inhabiting false ceilings if maintenance is neglected. Pollutants or airborne pathogens can enter damaged HVAC vents and circulate in the building, spreading diseases through the air if maintenance is not regularly carried out. Thus, sporadic checks of false ceilings can lead to the failure of amenities such as HVAC or lighting fixtures, causing problems for the occupants using the rooms below. The need for frequent inspection and maintenance puts a heavy strain on the skilled workforce. These people have to work at height and continually with the risk of falls. Falls from high heights can cause severe contusions, bone fractures, and other injuries. These injuries can prevent human workers from working for extended periods of time while they recover. Maintenance companies can also face financial losses and manpower shortages when injured personnel are unable to work. The existing false ceiling maintenance process is greatly dependent on human labour. With the myriad of obstructions that exist within false ceilings and the poorly lit conditions, there are many risks faced by human workers during the inspection phase of false ceiling maintenance. The components in the plenum are often laid for convenience during construction instead of ease of access and maintenance. Disorganised wiring, piping and the haphazard arrangement of other elements can cause higher occurrences of injuries to human workers. This does not exclude unexpected encounters with pest infestations [9] or the dislodging of heavy items while performing maintenance in the plenum. Each false ceiling site is different across every building and sometimes varies among individual floors due to differing requirements in fixtures and amenities. Design guidelines are often neglected for ease of installation and meeting tight deadlines. Wiring and the compacted arrangement of fixtures close together can pose as navigational and visual obstructions for inspection tasks, even for robotic aids. There are studies that look into automated inspection solutions to alleviate the burden on skilled human labour for false ceiling inspection works. Many research interests in robotic solutions have been taken up in recent years to aid human workers in the field of maintenance for the built environment [10; 11]. These mobile robotic solutions are often made small and lightweight to navigate tight and hard-to-reach spaces and are often installed with cameras to conduct visual inspection [12; 13; 14; 15]. However, using robotic means for such tasks still carries the risk of having the robot encounter obstacles within the false ceiling plenum and being stopped prematurely before completing its visual sweep of the area. With the haphazard layout of amenities in the false ceiling plenum, robots can get stuck due to its form or locomotion methods, getting caught by stray cables and pipes or the crowded layout of infrastructure within false ceilings. This is counterproductive for inspection works as manpower would still then be required for the manual retrieval of the robot. Self-righting robotic mechanisms have been explored in works such as [16] for toppled robots on inclined planes [17; 18], regarding usage of added tail mechanisms for self-righting, and even self-righting mechanisms used for jumping robots [19; 20].