Admittance Control for Robotic Loading: Design and Experiments with a 1-Tonne Loader and a 14-Tonne LHD

This paper describes the design, tuning, and extensive field testing of an admittance-based Autonomous Loading Controller (ALC) for robotic excavation. Several iterations of the ALC were tuned and tested in fragmented rock piles—similar to those found in operating mines—by using both a robotic 1-tonne capacity Kubota R520S diesel-hydraulic surface loader and a 14-tonne capacity Atlas Copco ST14 underground load-haul-dump (LHD) machine. On the R520S loader, the ALC increased payload by 18 % with greater consistency, although with more energy expended and longer dig times when compared with digging at maximum actuator velocity. On the ST14 LHD, the ALC took 61 % less time to load 39 % more payload when compared to a single manual operator. The manual operator made 28 dig attempts by using three different digging strategies, and had one failed dig. The tuned ALC made 26 dig attempts at 10 and 11 MN target force levels. All 10 11 MN digs succeeded while 6 of the 16 10 MN digs failed. The results presented in this paper suggest that the admittance-based ALC is more productive and consistent than manual operators, but that care should be taken when detecting entry into the muck pile

Analysis of Poverty Dynamics in Canada (Working Paper 9)

While we know much about poverty (or “low income”) in Canada in a static context, our understanding of the underlying dynamics remains very limited. This is particularly problematic from a policy perspective and the country has been increasingly left out on an international level in this regard. The contribution of this paper is to report the results of an empirical analysis of low income (“poverty”) dynamics in Canada using the recently available “LAD” tax-based database. The paper first describes the general nature of individuals’ poverty profiles (how many are short-term versus longterm, etc.)., the breakdown of the poor population in any given year amongst these different types, and the characterisation of poverty profiles by sex and family type. It then reports the estimation of various econometric models, starting with a set which specifies entry into and exit from poverty in any given year as a function of a variety of personal attributes and situational characteristics, including family status and changes therein, province of residence, inter-provincial mobility, language, area size of residence and calendar year (to capture trend effects). A set of proper hazard models then adds duration effects to these specifications to see how exit and re-entry probabilities shift with the amount of time spent in a poverty spell or after having exited a previous spell. A final set of specifications then investigates “occurrence dependence” effects by including past poverty spells first in an entry model and then with respect to the probability of being poor in a given year. Policy implications are discussed.

An Investigation into the Failure to Implement a Universal School Lunch Program during WWII and Postwar Reconstruction in Canada: The Case of Ontario

The purpose of this research is to investigate the various social, political and economic factors that contributed to Canada’s failure to implement a universal school lunch program during the 1940s. Although Canada developed several other social welfare programs in the post-war period, it remains one of the only industrialized nations that does not provide hot meals to children in elementary or secondary schools. Data from the province of Ontario, a major site of postwar reconstruction and policy-making, has been taken up to inform the broader national discourse on school lunches from the 1940s. National, Ontario provincial and City of Toronto archival records were collected and analyzed according to common themes, in order to identify key barriers that constrained government support of a hot meal program. Archival records were identified using key words, and were limited to materials created between 1930-1952. Analysis suggests that sufficient need for a hot meal program had not been established during the 1940s. Despite misleading nutrition messages, rates of malnutrition and nutrient-related disease were at an all-time low, and many Ontario school boards did not appear to have the necessary infrastructure required to supply all pupils with hot meals. The Canadian government had already employed significant resources to improve existing social security programs by coupling them with health education. This strategy reflected a shift in understanding malnutrition as a knowledge-based problem, as opposed to income-based. This understanding was further reinforced through the moralized dissemination of nutrition information, which placed blame on women for improperly raising their children. Ultimately, the strong uptake of nutrition as a public health issue in Ontario may have limited prospective responses to solutions already utilized in the public health domain, and directed favour away from a universal school lunch program for Canada.